TECHNICAL NOTE

FINAL REPORT

CONTRACT NAS8-28988

N77191521111111111111111111111111111

TN-FT-76-4

METHODS FOR DATA REDUCTION AND LOADS ANALYSIS

OF

SPACE SHUTTLE SOLID ROCKET BOOSTERMODEL WATER IMPACT TESTS

SEPTEMBER 1976

Prepared by

AERO IHYDRODYNAMIC S GROUPADVANCED DEVELOPMENT DEPARTMENT

CHRYSLER CORPORATION SPACE DIVISIONNEW ORLEANS, LOUISIANA

REPRODUCED BY, NJlIu.s. Department of Commerce

National Technical Information ServiceSpringfield, Virginia 22161

SUMMARY

This report presents the methodology used to predict full-scale Space Shuttle

Solid Rocket Booster (SRB) water impact loads from scale model test data.

Tests conducted included 12.5 inch and l20inch diameter models of the SRB.

Geometry and mass characteristics of the models were varied in each test series

to reflect the current SRB baseline configuration. Nose first and tail first

water entry modes were investigated with full-scale initial impact vertical

velocities of 40 to 120 ft/sec, horizontal velocities of 0 to 60 ft/sec., and

off-vertical angles of 0 to ±30 degrees. The test program included a series of

tests with' scaled atmospheric pressure.

Scaling relationships were established analytically and later verified by test.

Full-scale equivalent loads were subsequently estimated by applying these scaling

relationships to the model test data for the current SRB baseline configuration.

Load distributions on the cylindrical body, aft bulkhead, nozzle and skirt were

predicted for the significant dynamic events of initial impact ,cavity collapse,

maximum penetration, rebound and slapdown.

Loads developed during water impact were found to have a significant influence

on the structural design of the SRB. Initial impact loads are critical to

the design of the nozzle, aft skirt, aft bulkhead, lower cylindrical body

and auxiliary components mounted in the nozzle-skirt annulus region. Loads

developed during cavity collapse also define design requirements for the aft

skirt and lower cylindrical body. Hydrostatic loads developed during maximum

penetration are significant to the design of the lower cylindrical body,

i

while slapdown loads influence the design of upper cylindrical body and

forward Skirt.

This study was conducted in support of the NASA/MSFC Booster Recovery Program

under NASA/MSFC Contract NAS8-28988.

ii

TABLE OF CONTENTS

PAGE

LIST OF ILLUSTRATIONS v

LIST OF TABLES x

1.0 INTRODUCTION 1-1

2.0 TEST MODELS AND INSTRUMENTATION 2-1

3.0 TEST PROGRAMS 3-1

3.1 TEST SERIES C-143 3-13.2 NOL 12.5 INCH MODEL TEST 3-23.3 TEST SERIES C-145 3-23.4 TEST SERIES P-015 3-33.5 TEST SERIES P-022 3-33.6 TEST SERIES P-029 3-43.7 TEST SERIES TMS-333 3-43.8 TEST SERIES UNO-l 3-5

4.0 DATA ACQUISITION AND PROCESSING 4-1

5.0 SRB WATER IMPACT DYNAMIC EVENTS 5-1

5.1 INITIAL IMPACT 5-15.2 CAVITY FORMATION AND COLLAPSE 5-4

. 5.3 MAXIMUM PENETRATION 5-75.4 REBOUND AND SLAPDOWN 5-7

6.0 SCALING RELATIONSHIPS 6-1

7.0 DATA ANALYSIS 7-1

7.1 INITIAL IMPACT 7-37~2 CAVITY COLLAPSE 7-67.3 MAXIMUM PENETRATION 7-107.4 SLAPDOWN 7-10

8.0 FULL SCALE LOADS 8-1

8.1 INITIAL IMPACT 8-18.2 CAVITY COLLAPSE 8-118.3 MAXIMUM PENETRATION 8-178.4 SLAPDOWN 8- L88.5 COMPONENT Lo.~DS 8-23

8.5.1 NOSE CONE FRUSTUM LOADS 8-248.5.2 SYSTEM TUNNEL LOADS 8- 268.5.3 E. T. ATTACH RING LOADS 8-26

iii

TABLE OF CONTENTS (CONTINUED)

PAGE

8.5.4 AFT SEPARATION MOTOR LoADS 8-278.5.5 TVC PACKAGE LOADS 8-278.5.6 NoZZLE ACTUATOR LOADS 8-288.5.7 HEAT SHIELD/AFT END RING LOADS 8-308.5.8 SRM CLEVIS JOINT PIN RETAINER BAND LOADS 8- 31

9.0 REFERENCES 9-1

APPENDIX A TYPICAL SET OF MODEL TEST DATA A-I

APPENDIX B SCALING OF TAIL-FIRST, VERTICAL WATER B-1ENTRY MODEL TESTS OF THE SPACE SHUTTLESOLID ROCKET BOOSTER

iv

FIGURENUMBER

2-1

2-2

2-3

2-4

2-5

2-6

3-1

4-1

5-1

5-2

5-3

6-1

6-2

6-3

6-4

6-5

6-6

LIST or ILLUSTRATIONS

TITLE

156 Inch-Diameter SRB Configuration

Space Shuttle Solid Rocket Booster 4/11/73Baseline Configuration

11/1/75 Baseline SRB Water Impact Configuration

Basic Model, 4-11-73 Configuration

Pressure Transducer Locations, 4-11-73Configuration

Accelerometer Locations, 4-11-73 Configuration

SRB Water Impact Loads Coordinate System

Data Acquisition and Processing Block Diagram

Qualitative Vehicle Trajectory During Impact

SRB Water Impact Dynamic Events

Cavity Development and Collapse

Comparison of 12.5 Inch and 120 Inch-DiameterModel Peak Internal Nozzle Pressures

Comparison of 12.5 Inch and 120 Inch-DiameterModel Internal Nozzle Pressures (Peak Values)

Comparison of 12.5 Inch and 120 Inch-DiameterModel Internal Nozzle Pressures (10 MilisecondAverage)

Comparison of 12.5 Inch and 120 Inch-DiameterModel Internal Nozzle Pressures (Peak Values)

Comparison of 12.5 Inch and 120 Inch-DiameterModel Internal Nozzle Pressures (10 Mi1isecondAverage)

Comparison of 12.5 Inch and 120 Inch-DiameterModel Peak Slapdown Pressure

v

PAGENUMBER

2-8

2-9

2-10

2-11

2-12

2.:..15

3-15

4-4

5-9

5-10

5-13

6-5

6-6

6-7

6-8

6-9

6-10

FIGURENUMBER

6-7

6-8

7-1

7-2

7-3

7-4

7-5

7-6

7-7

7-8

7-9

7-10

7-12

7-13

7-14

LIST OF ILLUSTRATIONS (Continued)

PAGETITLE NUMBER-

Comparison of 12.5 Inch and 120 Inch-Diameter Model 6-11Primary Slapdown Pressures (Peak Values)

Comparison of 12.5 Inch and 120 Inch-Diameter Model 6-12Primary Slapdown Pressures (10 Milisecond Average)

Typical Model Test Data (Test P015-70) 7-13

Pressure Distribution at Nozzle Toe-In (With 7-14Nozzle Extension)

Determination of Maximum Pitch and Axial Accelera- 7-15tion Times

Description of Vehicle Aft End Geometry (with 7-16Nozzle Extension)

Pressure Distribution at Maximum Pitch Acceleration 7-17(Without Nozzle Extension)

Pressure Distribution at Maximum Pitch Acceleration 7-18(With Nozzle Extension)

Correlation of Nozzle Pressure D2l 7-19

Extrapolation of Nozzle Pressures 7-20

Variation of Nozzle Internal Pressure with Impact 7-21Conditions, Maximum Pitch Acceleration

Pressure DistributiclU at Maximum Axial Acceleration 7-22(With Nozzle Extension)

Variation of Maximum Acceleration Levels with Impact 7- 23Conditions, Maximum Pitch Acceleration

Variation of Maximum Acceleration Levels with Impact 7-24Conditions, Maximum Pitch Acceleration

Normalized Shear Force, Beriding Moment, and Axial 7-25Force Distributions, Maximum Axial or PitchAccelerations

Qualitative Description of Cavity Formation and 7-26Collapse

vi

FIGURENUMBER

7-15

7-16

7-17

7-18

7-19

7-20

7-21

7-22

7-23

8-1

8-2

8-3

8-4

8-5

8-6

8-7

8-8

LIST OF ILLUSTRATIONS (Continued)

PAGETITLE NUMBER---

Typical cavity Collapse Radial Pressure Distribution, 7-28NOL 12.5 inch-Diameter Model

Cavity Collapse Pressure Distributions, SRM Case 7-29and Aft Skirt PresSures

Cavity Collapse Pressure Distribution Factor, Kc 7-30

Cavity Collapse Pressure Distribution Function 7-31Parameter, TJ

Variation of Penetration Depth With Impact 7-32Conditions

Variation of Angle at Maximum Penetration with 7-33Impact Conditions

Typical Time Histories of Slapdown Pressures 7-34

Typical Full Scale Trajectory for Vehicle C.G., 7-35Test P015-70

Qualitative Vehicle Trajectory During Impact 7-36

Correlation of Internal Skirt Pressures, Maximum 8-36Pitch Acceleration Event

Correlation of Bulkhead Pressures, Maximum Axial 8-37Acceleration Event

Correlation of C.G. Accelerations, Maximum Pitch 8-38Acceleration Event

Correlation of C.G. Accelerations, Maximum Axial 8-39Acceleration Event

Correlation of Peak Lee Side Cavity Collapse 8-40Pressure

Correlation of C.G. Accelerations at Cavity 8-41Collapse

SRB Water Impact Cavity Collapse Loads 8-425/1/75 Full Scale Configuration

Maximum Penetration Depth 8-43

vii

FIGURENUMBER

8-9

8-10

8-11

8-12

8-13

8-14

8-15

8-16

8-17

8-18

8-19

8-20

8-21

8-22

8-23

8-24

8-25

8-26

8-27

LIST OF ILLUSTRATIONS (Continued)

TITLE---Pitch Angle at Maximum Penetration Depth

MinUnum Expected Ullage Pressure for SolidRocket Motor

Typical Nose Pitch Acceleration Time History

Typical C.G. Pitch Acceleration Time History

Typical Slapdown Pressure Time History

Slapdown Pressure Distribution Procedure

Slapdown Pitch Angle (6LW) - Degrees

Slapdown Radial Pressure Distributions

Variation of Slapdown Keel Peak Pressure wjthImpact Condition

SRB Slapdown Dynamics

SRB Water Impact Slapdown Loads, 5/1/75 FullScale Configuration, Keel Pressure

SRB Water Impact Slapdown Loads, 5/1/75 FullScale Configuration, Applied Pressure andInertial Reaction Loads

SRB Water Impact Slapdown Loads, 5/1/75 Ful1Scale Configuration; Bending Moment

SRB Water Impact SlapdownLoads, 5/1/75 FullScale Configuration, Shear

Component Acceleration Load Factors

Surface Pressure Coefficients for SRB Nose ConeFrustum

Nose Cone Configuration and Coordinate System

Systems Tunnel Water Impact Pressure Distribu­tions

E.T. Attach Ring Water Impact Pressure Loads

viii

PAGENUMBER

8-44

8-45

8-46

8-47

8-48

8-49

8- 50

8-51

8-52

8-53

8-54

8-55

8-56

8-57

8-58

8-59

8-60

8-61

8-62

FIGURENUMBER

8-28

8-29

8-30

8-31

'8-32

LIST OF ILLUSTRATIONS (Continued~

TITLE

Aft Separation Motor Water Impact Load

TVC Package Water Impact Loads

Nozzle Actuator Water Impact Load

Heat Shield W~ter Impact Configuration

r - Function

ix

PAGENUMBER

8-63

8-65

8-67

8-70

8-71

TABLENUMBER

2-1

2-2

2-3

3-1

3-2

3-3

3-4

3-5

3-6

3-7

3-8

8-1

8-2

LIST OF TABLES

TITLE

Characteristics of the 156 Inch-DiameterConfiguration - Prototype and Models

Charac teristics of the SRB 4/11/7'.3 BaselineConfiguration - Prototype and Models

_Characteristics of the SRB 11/1/74 BaselineConfiguration - Prototype and Models

Test Matrix - Test Series C-143

Test Matrix - NOL 12.5 Inch Model Test

Test Matrix - Test Series C-145

Test Matrix - Test Series P-015

Test Matrix - Test Series P-022

Test Matrix - Test Series P-029

Test Matrix - Test Series TMS~333

Test Matrix - Test Series UNO-1

Nose Cone Frustum Trajectory Listing

SRM Nozzle Actuator Response Loads

x

PAGENUMBER

2-5

2-6

2-7

3-6

3-)

3-8

3-9

3-11

3-12

3-13

3-14

8-32

8-33

SECTION 1.0

INTRODUCTION

The initial stage of the Space Shuttle launch configuration will consist of

two parallel-burn solid rocket boosters (SRB). After burn-out, the boosters

will separate and return to earth for a sea landing. They will then be re­

covered at sea and subsequently refurbished for use again in later flights.

Although a parachute recovery system will be used for deceleration prior to

impact, the SRB will land with considerable vertical velocity. In addition,

surface wi nds may superimpose appreciable drift velocities. Therefore, the

SRB will experience relatively high acceleration and pressure loads at the

time of impact and must be designed to withstand these loads in addition to

the normal operating loads imposed during the propulsive boost ascent and

stage separation phases.

In order to assess the magnitude and nature of these water impact loads and to

study the general feasibility of water recovery, a test program was

initiated using scale models of the SRB. Initial tests were conducted with

a 12.5 inch-diameter model, geometrically similar to the original SRB design,

which was a l56-inch diameter SRB. The objectives of these tests were to

evaluate entry modes, flotation attitudes, penetration characteristics, fun­

damental fluid dynamic characteristics, and to obtain preliminary design

loads. Additional tests were performed with a 120 inch-diameter Titan IIIC

SRB for the purpose of verifying scaling relationships previously determined

analytically. Results of these tests are described in References 4 to 8.

More recent tests were designed to study the SRB 4-11-73 and 11-1-74 baseline

1-1

configuration. In these programs, 12.5 inch-diameter models were used

to evaluate configuration effects and to assess the effects of wind

drift (horizontal velocity).

The data base accumulated during the scale model test programs has been

used to predict full scale water impact loads and assess the impact of

configuration changes as the SRB evolved from the original design to

the current 5/1/75 configuration. These loads for the various SRB con­

figurations have been published in References 1 to 3 and 30 to 33.

These loads have served as a basis for trade studies related to SRB

structural design and selection of the required recovery system. The

methodology used in the data reduction and subsequent analysis is pre­

sented here.

-1-2

SECTION 2.0

TEST MODELS AND INSTRUMENTATION

The configurations used in these. tests were of two basic designs, a modified

Titan III-C SRB and the 4-11-73 baseline SRB configuration. The modified

Titan III-C SRB design, 156 in. in diameter, reflects initial thinking on

the Space Shuttle design concept which called for a booster with fixed,

canted nozzle, shielded by a straight skirt as illustrated in Figure 2-1.

Two instrumented models, one of 12.5 inch-diameter and the other of 120

inch-diameter, were fabricated and tested. Pertinent dimensions and mass

characteristics of the prototype and test models are given in TableT.

The 4-11.-73 baseline configuration reflects a later design decision to in­

corporate a gimballed nozzle for booster thrust control. The design, shown

in Figure 2-2, features a notzle whose neutral position is in line with the

vehicle axis and which is shielded by a flared skirt to permit gimba1ling.

Several variations of this configuration were tested with a 12.5 in. diameter

modeL The original configuration incorporated a full-length nozzle ("long

nozzle", "with nozzle extension"). Early testing indicated that water impact

loads on the nozzle were quite severe. In order to provide for relief of

these loads if later deemed necessary, the design option of jettisoning the

nozzle extension prior to water impact was incorporated into the program.

Therefore, a model configuration with shortened nozzle (~'short no?zle",

"without nozzle extension") was also tested to simulate· the case in which the

nozzle extension is jettisoned. The basic model was fitted with a conical

aft bulkhead. It was later modified to incorporate a spherical aft bulkhead

2-1

and was further modified to incorporate a baffle in the nozzle-skirt annulus

region to protect the aft bulkhead from the severe pressure loads of initial

impact as experienced earlier 'in tests with the short nO?zle configuration.

Pertinent dimensions and mass characteristics of the 4-11-73 configuration and

models used in the different tests (discussed in the following sec tion) are

given in Table II.

The models were designed with sufficient strength to behave under load effec­

tively as rigid bodies. Total weights center of gravity and pitch moment of

inertia were scaled as well as possible within the many constraints of design

and instrumentation requirements. As can be seen in the tables s the models

were overweight by no more than 15%, the center of gravity was within 6% (of

model length) of the design locations and pitch moment of inertia was within

:hO% of the design value. No attempt was made to scale mass distribution or

elastic properties of the full-scale vehicle since the structural design was

still in its embryonic stages at the time and subject to certain change.

Moreover, such scaling would have imposed serious limitations and restric­

tions on the amount and location of instrumentation installed on the model.

The basic model, used for the primary tests (MSFC Test No. P-015) of the 4-11-73

configuration is shown in figure 2-4.

The models were instrumented with approximately 50 transducers to measure

pressures, accelerations and strains. Transducers were strategically located

to give maximum, or otherwise significant, measurements on the cylinder, aft

Skirt, nozzle and bulkhead. Three sets of axial, pitch and yaw accelerometers

were located near the nose, center of gravity and tail to aid in determining

total vehicle loads. Pressure transducer and accelerometer locations for the

2-2

basic 4-11-73 configuration model are shown in figures 2-5 and 2-6. Strain

gages were distributed so as to determine local stresses over the vehicle

and shear, bending moment and axial force at one station. Pressure trans-I

ducers were located so as to aid in determining the loads on individual com-

ponents and to help in assessing the fluid dynamics involved in the water

impact. Slight variations in the type, number and location of transducers

were made to meet the data requirements defined by individual test objec-

tives. In all cases, an epoxy potting compound and silicone grease were

used to waterproof the instruments, and RTV was added to protect the trans-

ducers from thermal shock at water entry. Nevertheless, strain gages bonded

to.the vehicle skin were quite susceptible to damage during test, and very

little data was obtained from them. Due to the shortcomings in strain data

no attempt was made at stress analysis in the present study. However, such

analyses have been made, using data from the 120 inch-diameter model, and

are reported separately in References 13 and 14. Accelerometers and pressure

transducers were bench-calibrated in the MSFC Metrology Laboratory prior to

installation in the model, and calibration resistances were determined for

purposes of electrical simulation of the calibration signal iater during

testing.

Signal conditioning equipment was packaged in a sealed instrumentation canis-

ter mounted inside the mode~ near its center of gravity. The canister con-

tained approximately 60 Wheatstone bridge balance circuits and three 21~chan-

nel constant bandwidth multiplexers .. Each multiplex system had a 96 kc center

frequency and 10 channels on 8 kc spacing each side of center frequency. All

channels had a 12 kc bandWidth.

2-3

The models were painted with longitudinal stripes along the 90 0 meridians

and circumferentially at three axial locations to aid in the analysis of

high speed photographic data.

2-4

\

---156 Inch-Diameter SRB Configuration

Configuration Design Scale Models - As Built

Full-Scale 120 in-Diam. 12.5 in-Diam. C-l45 Test Series C-l43 Test Series NOLPrototype Scale Model Scale Model Confilmrat ion Configuration 12.5 in. Model

mgth, in. 1351 1040 108.4 1056.7 108.4 108.1(1151.7)

1151. 7

ldy Diam., In. 156 120 12.5 121.1 12.5 12.5e21.1 )121. 1

:>zzle Exit Diameter, 163.8 126.1 13.1 77.5 13.1 13.1In. (126.1)

126.1

lzzle Throat Dia- 54.6 42.1 4.37 46 4.37 4.37meter, In.

(:~ ):>zzle Expansion 9~0 9.0 9.0 2.8 9.0 9.0Ratio (Area) (7.5)

7.5

eight, Lbs. 190,000 87100 97.7 84500 101. 0 97.8

(87700)88500

.G., in. aft of 618 476 49.4 485.6 55.32 52.75Fwd Cylinder End (505.4)

509.9

itch Moment of Iner- 7.22X106 1. 95Xl06 23.6 1.8X106 20.4 23.61tia., Slug-Ft. 2 ( 2X106 )

2X106

C

p

w

B

N

N

L

NI

\J1 N

NOTES: (1) Values quoted are for water impact configuration (without nose cone, frustum, or-recovery system).(2) Values in ( ) are for the configuration with standard and reinforced nozzle extension; Le.,­

(standard nozzle extension)(reinforced nozzle extension)

TABLE 2-1. Characteristics of the 156 inch-Diameter Configuration - Prototype and Models

!')I

0'\

4-11-73_Baseline Configuration

Configuration Design 12.5 in-Diam. Scale Models - As Built

P-015 Test Series P-022 Test Series P-029 Test SeriesFull-Scale 12.5 in-Diam. Configuration Configuration ConfigurationPrototype Scale Model

(Conical Bulkhead) (Spherical Bulkhead) Spherical BulkheadShort Nozzle

! with Baffle1553 (1) 136.7 136.9 138.8

'Length, in. (1501) (2) (132.1) (132.3)(3) (132.3) (3) (132.3) (3)

Body Diam., in. 142 12.5 12.5 12.5(142) (12.5) (12.5) (12.5) (12.5)

-Nozzle Exit 142 12.5 12.5 12.5

Diameter, in. (105) ( 9.25) ( 9.25) ( 7.4) ( 7.4)-Nozzle Throat 53.4 I 4.7 4.7 4.7

Diameter, in. (53.4) I (4.7) (4.7) (4.7) (4.7)-_. -

Nozzle Expansion ! 7.1 7.1 7.1 7.J.Ratio (Area) (4.6) (4.6) (4.6) (2.5) (2.5)

-

Weight, Ibs.146,365 (4) 99.8 116.7 115.6

(143,165) (97.7) (114.4) (113.0) 111.0-----C.G., in. Aft of I 864.3 76.1 74.3 73.2

Fwd. Cylinder End (850.1) (74.8) (73.5) (71.8) (70.6)

Pitch Moment of 7.1l8x1Q6(4) 37.6 34.0 39.7Inertia, Slug-ft. 2 6.832xl06 36.0 31.5 (39.0) (38.5)

NOTES: (1) Values quoted are for water impact configuration (without nose cone, frustum, or recoverysystem.

(2) Values in ( ) are for nozzle extension removed; i.e., llshort nozzle".(3) Includes forward bulkhead lip.(4) Total mass and mass distribution taken from Ref. 15 for water impact configuration.

TABLE 2-2. Characteristics of the SRB 4-11-73 Baseline Configuration - Prototype and Models

NI

.......

Length - Inches

Body DiameterInches

Nozzle Exit DiameterInches (ShortNozzle)

Nozzle Throat Diameter

Weight - Pounds

C.G. Aft of FwdCylinder End

Pitch Homentof InertiaSlug-Ft2

Configuration Desi~~_ 12.5 Inch Diameter12.5 Inch Diameter Hodel As Built

Full Scale Model Scale lMS-333 Test

1530.2 131. 01 131.01

146 12.50 12.5

107.7 9.22 9.22

54.4 4.66 4.66

159706 100.2 107.2

891.4 76.3 77 .1

8.33 x 106 38.3 40.9

I.-

TABLE 2-3. Characteristics of the SR13 11-1-74 BaselineConfiguration­Prototype and Model

,165DIA

J-156DIA.

1519

1393

1304

78·1I

827

1037

II 6°.r=

/-----s - --

~ /

--NI

ex>

SPLASHDOWN MASS PROPERTIESWEIGHT: 190,000 LBS.PITCH MOMENT OF INERTIA: 7.2X106 SLUG-FT2

FIGURE 2-1. 156 INCH-DIAMETER SRB CONFIGURATION

1741

1474

I Xs ~ 1252.3 t PiVot

188 ---"'I 1504-- I r 145

l--tI ~1r- 1216 I -1 r. 93 "'+{15__

2--_--:..-

-t= I! I _ _ I I --- :-r r\jt'j__-----I-- -+ I-

I 141.7 192

,- -! L142 Diameter --- I -:: ----L-_

NI

\0

Xs • 200Xs = 1796

Weight at Waterl C.G. LocatiCXlImpact (Lbs.)

146,365 I Xs = 1252.3

. FIGURE 2-2 Space' Shuttle Solid Rocket Booster 4/11/73 Baseline Configuration

XB 395.0 XB 1930.64

1535.64

XB 1823.85(TANGENT)

SEPARATION HOTOR

CAVITY COLLAPSE RING

SYSTEMS TUNNEL

ET ATTACH RING

146.0 DIA.

CASE SEGMENT JOINT

XB 531.98(TANGENT)

" -r+- . . I .. . I ;:~'~ 208.2 DIA.I I .'["8 -l,-J±I.,-l· 0-1 -1±il1ffJf-j =-t

NI.....o

XB 371.0

SPLASHDOWN HASS PROPERTIES:WEIGHT = 158,667 LBS.PITCH MOMENT OF INERTIA = 8.318 X 106 SLUG-FT2

FIGURE 2-3 - 11/1/74 BASELINE SRB WATER I~PACT CONFIGURATION

N()to: Dllllf'I1Bionfl' nro ill 11ll:hcB

-I . - .•. 1-1- [~ Et~·--+-+-~~

NI

I-'I-' Note

-

• Weight (lb)--Full Length Nozzle:: 11E- -Short Nozzle:: 114. 4

• Model I (Slug-Hz) .--Full Length Nozzle:: 33.--Short Nozzle:: 31. 46I

-l[ 9.2I i- - I 1/~-----J -.-___,,'" I

'" I

16. 5

i-.lr-12. 5

-l!I ,- 0'-- ... I

_.....",.~"",.

~4. 7

i

15 0 ----1

~t.:~l '!" <?-~_2't:: >~ozz~e--s.t. ,") :- -: .. 7<: ~ '! l '";

FIGURE 2-4. BASIC MODEL, 4-11-73 CONFIGURATION

Note: Dimensions are in inches

-.D 0"- 0"- 0 -.D 0 -.D ...... -.D 0 -.D 0"-0 ...... - 0 0 0 U'1 C"'1 0 0 U'1 ....... . - . . . . . .eo -.D ~ C"'1 N C"'1 C"'1 ~ U'1 -.D -.D ~

N C"'1 ~ U'1 -.D r- eo 0"- 0

n I I I lei I I I I I L............-

......

11 'I' 'I' 'I' "I' 'I' I ' I' , 'I' 'I' 'I' ! J I' 'I' 'j' ....

I J 1 J 1 1 l J ", 1 l 1......0 ,

0 0 0 0 0 J 0 0 0 0 -< - ' - N, I I I I I I I I I I I , .Q Q Q Q Q • Q Q Q Q Q Q C4 r-

AL -BL .-t-.:>I~t-.:,

D-20

---+- ~SO

D-06 § 1

Section A- A Section B- B

FIGURE 2-5 PRESSURE TRANSDUCER LOCATIONS, 4-11-73 CONFIGURATION(a) MODEL CYLINDER PRESSURE TRANSDUCERS

Note: Dimensions are in inches

D-26

D- 2 9-+-+--+ • _

Section /\- (I.Spdion J',. H

5. 75i

sl'b_~

A10.2--8_-+-__B_.1-D:29 - -+--

~ 3.0

""",,-" D-26

"

.... D-24......

--'-4- ... D-25

FIGURE 2-5 CONTINUED. (b) FULL LENGTH NOZZLE AND SKIRT PRESSURE TRANSDUCERS

2-13

D- 28 --I::l-~---------

Section A-A

Note: Dimensions are in inches

D- Z9--1=+--+----+--

Section B- B

...." ..... ..... ,)ii

........ D:3J.t- D-22 I

Ai ;- B~ !-f--+ _-.:..:-+--- -+ .--+--+-

D-28 1 D-Z9

",J- _ . D-Z5 ~// -----.l~J

,/"", ~D-26

,Lll'Y Oli' THill", ~'IS POOI~

FIGURE 2-5 CONTINUED. (c) SHORT NOZZLE AND SKIRT PRESSURE TRANSDUCERS

2:'14

., Note: DimensioQ..3 are in inches

• EA009• EY008

EP007

JJLO.7;-'B--Il-z.o

.~.

EY005 \\EA006

EP004.· \ '\.

i - --.

A~l. Z3

Z.O

!'-)I...,:.d,

EPOOl

1. Z4

EY002EA003

EP004

1. 24

EP007

1. 24 5.25

'"""'- EAO 09EY008

Section A-A SeCtion B- B Section C- C

FIGURE 2-6. ACCELEROMETER LOCATIONS, 4-11-73 CONFIGURATION

SECTION 3.0

TEST PROGRAM

The test program consisted of a number of drop tests, using the scale

models of the SRB described in Section 2.0. The tests were conducted at

the NASA/MSFC Over Water Launch (OWL) Tank Facility in Huntsville, Ala­

bama: the Naval Ordnance Laboratory (NOL) Hydroballistics Tank in White

Oak, Maryland; The University 0 f New Orleans, New Orleans, Louisiana~ and

the Long Beach Naval Shipyard (LBNS), Long Beach, California. The drops

were made into calm water, in the nose-first and tail-first entry modes~

impact conditions varying with entry velocity and pitch angle. Defini­

tion of the entry parameters is illustrated in Figure 3-1. The test pro­

gram consisted of eight series of tests, conducted in the following

chronological order:

3.1 Test Series C-143

These were the initial tests of the program and were conducted in the

OWL tank during the period ~ovember 1972 to April 1973, in accordance

with the requirements of Reference 9. A total of 114 tests were con­

ducted, using a 12.5 inch-diameter model of the 156 inch-diameter SRB

configuration. The objectives of these tests were to evaluate entry

modes, flotation attitudes, penetration characteristics, fundamental

loads. Nose-first and tail-first entry modes were investigated, with

impact conditions covering the full-scale range of vertical velocity,

Vv = 80 to 120 ft/sec, horizontal velocity, VH = 0 to 50 ft/sec, and

pitch angle, () = 0 to 30° (Fig. 3-1). The te s t matrix is shown in

3-1

Tab Ie 3- L A detailed description of the tests is presented in

Reference 4.

3.3 Test Series C-145

These tests w~re conducted at the LBNS facility during the period Febru­

ary 10 - March la, 1973, in accordance with the requirements of Refer­

ence 6. A total of 22 tests were conducted, using a 120 inch-diameter

model of the 156 inch diameter SRB configuration. In addition to the

fundamental objectives of the earlier test series, these tests were con­

ducted to verify scaling relationships. All tests were in the tail-first

entry mode, with Vv = 8 to 80 ft/sec, VIi = 0 and () = 10 to 30°. The test

3-2

matrix is shown in Table 3-3. A detailed description of these tests is

presented in Reference 7.

3.4 Test Series P-015

These tests were conducted in the OWL tank during the period July 1-27,

1973, in accordance with the requirements of Reference 16. A total of

127 tests were conducted, using a 12.5 inch-diameter model of the

4-11-73 baseline configuration (with and without nozzle extension), to

evaluate the effects of drift velocity and the updatedSRB configuration.

The tail-first =ntry mode was investigated, with Vv = 80 to 120 ft/sec,

VH = 0 to 60 ft/sec and 9 = 0 to ~30°. The test matrix is shown in

Table 3-4. A detailed description of these tests is presented in

Reference 17.

3.5 Test Series p-022

These tests were conducted in the NOL tank during the period September

9-19, 1973, in accordance with the requirements of Reference 18. A

total of 30 tests were conducted, 22 of them at scaled atmospheric

pressure (1.29 psia). The model used was the same as for the P-015

tests, except that it was modified to include a hemispherical bulkhead.

The primary objective of the tests was to evaluate the effects of press­

ure scaling. The tail-first entry mode was investigated with the ;same

range of impact conditions as for the P-015 tests, except that wind drift

velocity was not simulated (i.e., va = 0). The test matrix is shown in

Table 3-5, and a detailed description of the tests is presented in

References 19 to 21.

3-3

3.6 Test Series p-029

These tests were conducted in the OWL tank during the period November

9-20, 1973. A total of 47 tests were conducted over the same range of

impact conditions as for the P-022 tests. An tests were with tail­

first entry, using the short-nozzle configuration of the P~022 model,

modified to include an elliptical bulkhead and a baffle in. the nozzle­

skirt annulus region. The objectives of these tests were to evaluate

the effectiveness of the baffle to shield the bulkhead region and to

study lee-side cavity collapse pressures. The test matrix is shown

in Table 3-6, and a detailed description of the tests is presented in

Reference 22.

3.7 Test Series TMS-333

Water impact tests using a 12.5 inch scale model of the 11/1/74 con­

figuration Space Shuttle Solid Rocket Booster were conducted during

October 1974 at the Naval Surface Weapons Center, White Oak~ Maryland

in accordance with the requirements of Reference 25. The objective of

this test program was to measure accelerations, forces, and pressures

imparted to the SRB Model during the initial impact, cavity collapse,

and slapdown phases of water entry.

A total of 69 tail first drops were made during this .test. Model

entry conditions simulated full scale vertical velocities of 80 and

100 ft/sec with horizontal drift velocities up to 45 ft/sec and impact

angles over a tlO° range. These tests were conducted at both ambient

and scaled atmospheric pressures. The test matrix is shown in Table

3-7 and a detailed description of the test is presented in Reference

26.

3-4

,-

3.8 Test Series UNO-l

Water impact tests using a fore-shortened 12.5 inch diameter model

simulating the aft cylinder and nozzle/skirt geometry of the 11/1/74

and 5/1/75 configurations of the Space Shuttle Solid Rocket Booster

were conducted during September 1975 at the University of New Orleans

School of Engineering Hydrodynamics Tank, New Orleans, Louisiana in ac­

cordance with the test plan of Reference 28. The objective of this pro­

gram was to evaluate changes in nozzle loads for the 5/1/75 configuration

due to the addition of the compliance ring and a one-foot extension of

the nozzle)and to substantiate the analytically defined increase of

nozzle loads of the 5/1/75 baseline update.

A total of 49 drops were made with five geometric configurations. Model

entry conditions simulated full scale vertical velocities of 70, 80, and

90 FPS with water impact angles of 0, 5, and 10 degrees. Horizontal

drift velocity was not simulated in this test which was conducted at

atmospheric pressure. The test matrix is shown in Table 3-8 and a detailed

description of the test is presented in Reference 29.

3-5

WI

0"1

-~"-" f!""

;:;:1""r-4 ~e

~~Zc>. Vt""C::o~§c;;t""'t'38OO~

'"dO8:~.~

t-J

TABLE 3-1

TEST MATRIX - TEST SERIES C-143

C/>*=OO \Tn = 0 FPS -VV V'H ~ (I =10u (J =20°FPS FPS _20° _10° 0° 10° 20° 30° 90° C/>·k Vv=80 Vv=100 Vv=120 Vv=80 Vv=100 Vv=120

10 0 X 0° X X X X X X

0 X X X X X 22.5° X X X X X X

20 25 45° X X X X X X

50 X X 67.5° X X X X X X

0 X X X X 90° X X X X X X

40 25 X X X X X 112.5° X X X X X X

50 X X X 135° X X X X X X

0 X X X X 157.5° X X X X X X

60 25 X X X X X 180° X X X X X X

50 X X X X X

0 X X X X

80 25 X X X X X *<1> DENOTES MODEL ROLL ANGLE

50 X X X X X

100 0 X X X X

120 0 X X X X

.J! )

TABLE 3-2

TEST MATRIX NOL SERIES #1207

P if> Vv 8PSIA DEGO FT/SEC 0° 10° 20° . 3D"

14.7 0° 40 X X X X

J60 X X X X

100 X X X X

45° 40

j 60 - X X X,100 X X

1.53 0° 40 X X

t 60 X X X X

100 X X X X

45° 40

1 60 X X X

100 XX X

2.5 0° 60 X

4.0 X

8.0 X

3-7-': ,

TABLE 3-3

TEST MATRIX - TEST SERIES C-145

REINFORCED STANDARD NOVv NOZZLE EXTENSION NOZZLE EXTENSION NOZZLE EXTENSIONFPS 100 200 30° 10° 20° 30° 10° 20° 30°

10 X X X X

20 X X X

40 X X X X X

60 X X X X X X

80 X X

3-8

TABLE 3-4a

TEST MATRIX - TEST SERIES P-015WITH NOZZLE EXTENSION

..

Vv VH ~ c

FPS FPS _20° _10° 0° 10° 20° 30°X,~ X* X'~ X*0

60 30X

60

X* X* Xi(X'~0

X X X X Xi(80 30

X X X X X60

0x* x* x* X,~

X X X X X,~

100 30

X X X X X60

0X X,'( X,'( Xi(

X X X X X*120 30

X X X X X60

* Model rolled 180°

3-9

TABLE 3-4b

TEST MATRIX - TEST SERIES P-015WITHOUT NOZZLE EXTENSION

Vv VII ()

FPS FPS -20° _10° 0° 10° 20°

0 X X X

80 30 X X X X x*

60 X X X X x*

0 X X X

100 30 X X X X X*

60 X X X X x*

0 X X X

120 30 X X X X x*

60 X X X X x*

*Model rolled 180°.

3-10

TABLE 3-5

TEST MATRIX - TEST SERIES P-022WITH NOZZLE EXTENSION

Pa Vv 6PSIA FPS 0° 10° 20° 30°

80 X X X

1.29 100 X X

120 X X X X

80 X X

14.7 100 X X..

120

WITHOUT NOZZLE EXTENSION

Pa Vv 6PSIA FPS 0° 10° 20° 30°

80 ~ X X

1. 29 100 X X X

120 X X X .X

80 X X

14.7 100 X X

120

3-11

TABLE 3-6

TEST MATRIX - TEST SERIES P-029WITH NOZZLE EXTENSION, rp = 180°

Vv ~~

FPS 0° 10°

80 X X

100 X X

120 X X

WITHOUT NOZZLE EXTENSION, 4> = 180°

Vv (J

FPS 0° SO 10° ISo 30°

80 X X X X

100 X X X X* X*

120 X X X X* X*

*Model rolled 90°

WITHOUT NOZZLE EXTENSION, WITH BAFFLE, 4> =0°

Vv ()FPS 0° 10° 20° 30°

80 X X X X

100 X X X X

120 X X X X

3-12

TABLE 3-7DROP NUMBER MATRIX NOL TEST TMS-333

9i,.

Vv VH Po:> t/> .'

,..10°, _5° 0° +5° +10°

80 0 14.7 Q X X X'.

15 X~

30 , X-45 X X X

0 120 X X

15

30

45 X

0 1.26 0 X X X

15 X X X X

30 X X X

45 X X

0 120 X X

15 X X X X

30 -45

100 0 14.7 0 X X X

15 X

30 X

45 X X X

0 120 X X

15

30

45 X

0 1.26 0 X X X

15 X X X X

30 : X X X

45 X X

0 120 X X

15 X X X X

30

45 X X

3-13 llEPllODUC1B1LITY 'oF -THEORIGINAL PAGE IS pOOR

TABLE 3-8 TEST MATRIX - TEST SERIES UNO-1

IMODEL SCALE IFuLL SCALEINITIAL IMPACT ANGLEMODEL VERTICAL VERTICAL

CONFIGURATION VELOCITY VELOCITYFT/SEC FT/SEC 0 5° 10°

..

A 20.5 70 X X X

23.4 80 X X X

26.3 90 X· X X..

B 20.5 70 X X ..X

23.4 80 X X X

I 26.3 90 X X X

..

C 20.5 70 X X X

23.4 80 X X X

" 26.3 90 X X X

D 20.5 70 X X X

23.4 80 X X X

~ 26.3 90 X X X

E 20.5 iU X X X

23.4 80 X X X

• 26.3 X90 X X

3-14

. AXIAL ACCELERATION

h

VH - HORIZONTAL VELOCITY

() - PITCH ANGLE

Cl - FLIGHT PATH ANGLE

NOTE: ALL VALUES POSITIVE AS SHOWN

Vv -VERTICAL VELOCITY

(Cl- ()) - EFFECTIVE UlPACT ANGLE

h - PENETRATION DEPTH

Cl

FREE WATER SURFACE

LATERALACCELERATION

()_ I !-....

VH

PITCH ANGULARACCELERATION

LVI

I-'VI

~

FIGURE 3-1 SRB WATER IHPACT LOADS COORDINATE SYSTEH

SECTION 4.0

DATA ACQUISITION AND PROCESSING

A wire cable was provided to carry the transducer signals from the onboard

signal conditioner to an instrumentation trailer for recording on analog

magnetic tape. The cable consisted of five wires to transmit power, elec­

trical calibrations, and three multiplexed data signals. It was attached

to the model near the C.G. and was dropped with and alongside the model

during testing to minimize forces applied to the model by the cable. In

the instrumentation trailer, seven tape tracks were used to record three

multiplexed data signals, a 50 KC tape speed compensation signal, model

release signal, IRIG-Btime, and a voice signal.

Prior to each test, with model suspended above the water, calibration

resistors were shunted across all transducers and pretest calibrations

taken. After recording data during the test, post test calibrations were

performed in a similar manner with the model in calm water. After each

test, the data tape was played back through a demodulator and recorded on

oscillograph charts. The oscillographs were then examined for data qual­

ity, polarity, and IRIG-B time. Based on the results of this examination,

modifications or improvements to the instrumentation were made as required

prior to subsequent testing.

The analog tape was then sent to the MSFC Computation Laboratory for digitiz­

ing and plotting. The tape was played back, one data· track at a time, with

the multiplexed signals passing through tuners with individual frequencies

corresponding to the center frequencies of the multiplex channels. Thus,

the original multiplex signal was separated into 21 individual signals.

4-1

These signals were then fed through a low pass filter (100 cps for test

series TMS-333 and 220 cps for all others) into a discriminator which

measured the deviation from center frequency and assigned to is a four digit

magnitude. Digitizing was carried out at the rate of 1000 samples per second.

The computer then read each discriminator in sequence, recycling to repeat

the process for the next millisecond in time. Computer time required for one

complete set of readings was approximately 8 microseconds.

During the digitizing, the computer tracked the 50 KC reference signal,

adjusting time to compensate for any minute variations in speed of the tape

transport of the original analog data recorder. Overall control of the

process was keyed to IRIG-B time. The analog tape was sampled during the

pretest calibration, the test (beginning before model release and continu­

ing through slapdown), and the post test calibration. Output from the

digitizing computer consisted of a digital tape containing IRIG-B time fol­

lowed by 44 data points for each measured quantity: each data point corres­

ponding to times one millisecond apart. This format was repeated until

all data had been included. The calibrations were then used to express

magnitudes of the digitized data in terms of engineering units, and all

values were corrected for zero biases.

Finally, the tapes were processed in a merge and reformat program which

converted the data to Fortran form and rearranged it on files in a pre­

scribed numerical sequence. A plot tape was generated and time histories

of all measured quantities plotted on a Stronberg-Carlson 4020 Plotter.

A schematic of the data acquisition and processing system is shown in

figure 4-1.

4-2

Photographic coverage for the tests was provided by 16 mm high-speed movie

cameras. In OWL Test Series P-015, P-029, and C-143, data cameras were

mounted above and below the waterline, while split image photography (with

the centerline of the camera lens at the waterline) was used in NOL Test

Series P-022 and TMS-J33. All cameras were above the waterline for LBNS

Test Series C-145. In all cases, one camera (or set of,cameras) was placed

in the model pitch plane, the other perpendicular to it. All were aimed

at the impact point. In the LBNS tests, an additional camera was mounted

inside the model to record the flow of water through the nozzle.

Camera speed was set at 250 frames per second. Timing lines were recorded

on the margin of the film for exact determination of frame speed. A rec­

tangular grid with horizontal and vertical lines one foot on center was

photographed on each reel of film to provide a linear distance calibration.

Flash bulbs, which illuminated at model release, were placed in the field

of view of the cameras to coordinate time with the electrical instrumenta­

tion.

4-3

Irig BSOkc RefVoice Time

t + Jf

Signal Voltage AnalogTransducer f--+ t- Controlled - ~ Osci llographSignal Conditioning

Osci lla torTape

j

1

Ca Ii bra tion ~

Scanner ...Signal

t, f

Oscilloscope Oscillograph

TEST SITE-- -- ~ -- -- -- - --

COMPUTER CENTERIt

Digital f-- Transducer r-- - Low Pass TunerTape Signal Discriminator Filter

Calibration .... , PSD/ASDOscillograph-----....

Analysis~

Signal

,Calibration

Digi ta 1 Plot 4Ci20& ReformatTape r Program PlotterProgram

A :+

Calibration Analysis --Constant Program

FIGURE 4-1 DATA ACQUISITION AND PROCESSING BLOCK DIAGRAM

4-4

SECTION 5.0

SRB WATER IMPACT DYNAMIC EVENTS

Water impact of the SRB as revealed by high speed photographic records

and measured data from the model tests allows a qualitative description of

entry phenomena. This description is best viewed as individual phases con-

sisting of initial entry, cavity formation and collapse,maximum penetra-

tion, and rebound and slapdown (Figures 5-1 and 5~2). Within these phases,

there are one or more distinct events Which establish possible design criteria

as indicated below:

Entry Phase

Initial Entry

Event

lkzzle Toe-in

Max. PitchAcceleration

Max. AxialAcceleration

Annulus Stagnation

Possible Design Criteria

External Crushing Pressure onNozzle Keel (Long Nozzle)

Normal Load on Nozzle and Skirt,Vehic Ie Bending Moment, Pressureson Nozzle & Skirt.

Axial Load on Nozzle, VehiclePressure Loads on Nozzle, Skirt

Crushing Load on Bulkhead

Cavity Forma- Cavity Collapsetion & Collapse

Max. Penetration Max. Penetration

Crushing Load on Aft Case & Skirt

Crushing Load on Aft Case

Rebound andSlapdown

Slapdown Crushing Load on Forward Case atVarious Times (to' t i , tZ)

5.1 Initial Impact

Nozzle Toe-in. As the vehicle enters the water, there is a very short

time interval following initial contact with the liquid free surface during

which only a portion of the nozzle extension is wetted. The remainder of

the vehicle is dry. For negative impact angles, this wetted portion is on

5-1

the keel side of the nozzle. If water entry is accompanied by appreciable

horizontal velocity (VH ~ '" 30 ft/sec), significant external nozzle keel

pressures result and the event is designated as nozzle "toe-in". Inthis

case, the component of fluid velocity normal to the body at impact is maxi­

mized. Pressures associated with this flow develop over the nozzle external

surface. The flow separates from the internal nozzle surface on the keel side

giving rise to near ambient pressure on the nozzle internal surface. As a re­

sult, the vehicle is subject to a momentary pitching moment, while the wetted

portion of the nozzle extension is subject to a local short-duration compres­

sion (buCkling) load. Nozzle toe-in, as a distinct event, is observed only

with the long nozzle configuration at the relatively high effective· impact

angles associated with large horizontal velocity and negative impact attitude.

Maximum Pitch Acceleration. As the vehicle penetrates further the increasing

flow of water into the nozzle and nozzle~skirt annulus compresses the entrapped

air in the motor case chamber. Due to the normal velocity component, the flow

is asymmetric, causing a build-up of fluid along the inner walls of the skirt

and nozzle on the lee side. The resulting pressure build-up over the external

keel and internal lee surfaces producing a considerable normal force and pitch­

ing moment on the vehicle. This time is designated the maximum pitch accelera­

tion event.

Maximum Axial Acceleration. Moments later, with continued penetration, the

nozzle flows full. Nozzle and skirt internal pressures rise sharply, producing

maximum hoop loads and for the configuration without nozzle extension, the noz­

zle/Skirt annulus stagnates by impact of the water head with the motor case

aft closure bulkhead. This produces the maximum vehicle axial acceleration

event and maximum local pressure loads on most of the appendage structure

and subsystem components. The time interval between maximum pitch and

5-2

and axial accleration is a function of effective impact angle', decreasing

with decreasing angle until the two events become indistinguishable [or near­

zero angles.

Annulus Stagnation (With Nozzle Extension). Although the vehicle has lost

considerable momentum during the deceleration of initial impact for the con­

figuration with nozzle extension, penetrating velocity is still sufficient

to cause flow past the nozzle to separate at the nozzle exit plane. As back

pressure builds up in the nozzle-skirt annulus region, the separating free­

streamlines from the nozzle exit plane diverge wi,th time. As a result, the

flow passage between separating free surface and vehicle skirt continually

decreases. About 30 maee. (ulodel scale) after the time of maximum axial ac­

celeration, the separating free streamline has diverged to the point where

it encloses the aft rim of the skirt. Therefore, oncoming flow is diverted

around the skirt, and flow into the nozzle-skirt annulus is completely cut

off. The annular slug of water entrained between the nozzle and skirt con­

tinues toward and finally stagnates on the bulkhead. There is a spike in

bulkhead pressure w~th a corresponding spike in axial acceleration, the mag­

nitude of which is much smaller than that of the earlier maximum axial accel­

eration event for this configuration. The associated loads on the nozzle

wall are compressive (buckling) from the throat to the aft end of the skirt

and tensile (hoop) from there to the exit plane.

Annulus Stagnation (Without Nozzle Extension)

With continued penetration a quasi-steady state flow is established in­

side the nozzle and internal pressures drop rapidly. In the nozzle/

skirt annulus a cavitating flow has been established along the walls as

- 5-3

a result of wakes from the nozzle compliance ring and the large struc­

tural rings inside of the skirt. Arter the water slug impacts the aft

closure, bulkhead pressures begin to decay to approximately·SO% of peak

value as a pressure wave reflects back through the annulus. Local press­

ure in the water increases and all internal cavitation collapses. Nozzle,

skirt, and bulkhead pressures rise with all areas being subjected to

approximately the same pressure which is on the order of 2/3 of the

peak bulkhead pressure during maximum axial acceleration. In addition

to compressive buckling, the stagnation results in a negative nozzle

axial load, pulling it away from the bulkhead, due to the stagnation

pressure being much larger than the nozzle internal pressures at this

time. For Some impact conditions the magnitude of the negative nozzle

axial force is approximately equal to the positive axial load during maxi­

mum axial acceleration.

5.2 Cavity Formation and Collapse

For a pure vertical entry, i.e. initial horizontal velocity and pitch angle

are zero, the cavity formation and collapse is symmetrical about the vehicle

centerline as shown in Figure 5-3. Vertical velocity for the caSe illustrated

is 100 ft/sec., full scale.

5-4

accommodate the 'penetrating vehicle. As the vehicle continues to penetrate,

its velocity decreases and less lateral momentum is imparted to the water.

The lateral momentum imparted to the water at the cavity wall is resisted by

the difference in pressure across the cavity wall. This pressure difference

is a result of hydrostatic pressure in the water and the ambient air pressure

in the open cavity. Near the surface this cavity restoring force is very small

and the maximum cavity diameter is developed at about one half vehicle diameter

below the original water surface. At greater depths, the combination of less

lateral momentum imparted to the water (due to reduced velocity) and the

greater restoring force on the cavity wall (due to increased hydrostatic

pressure) results in smaller maximum cavity diameters. Maximum total cavity

volume is developed wh~n the vehicle has enetrated about three vehicle

diameters. Beyond this point in the entry, the cavity wall about two

vehicle diameters below the water surface begins to close toward the

vehicle. The cavity then "collapses" rather uniformly over about two

vehicle diameters forward of the aft end of the vehicle skirt. A large

amount of air is trapped near the aft skirt and becomes entrained in the

water as illustrated. This collapse of the cavity onto the vehicle

causes large pressures on the vehic le aft case and skirt. After the "cav­

ity collapse" onto the vehicle, the remainder of the cavity (above about

two vehic le diameters below the surface) closes rapidly from the bottom.

This vertical closing of the cavity results in a jet of water being created

which sprays up from the original entry point.

If there is some horizontal velocity or pitch angle at impact, the cavity

formation is similar to the vertical case above but collapses asymmetri­

cally with respect to the vehicle. This is illustrated in figure 5-3 Eor

a case with zero horizontal velocity and a 10 degree pitch attitude at

5-5

impact. Vertical velocity is 100 fps in this case also. The water which

initially filled the nozzle/skirt annulus can be seen being expelled in

the early stageso£ cavity development. The cavity boundaries are some­

what straighter, in the pitch plane shown, than for the symmetrical entry

discussed above. Al though the cavity is asymmetric with respect to the

vehicle, it is nearly symmetric with respect to the vertical. As the

cavity starts to collapse, the keel side cavity wall encounters the velli­

cle which is also tending to pitch into the cavity wall due to pitch rates

induced during initial impact. This event, denoted cavity "wall slap" in­

duces significant pressures locally, but are higher frequency and of lower

magnitude than the subsequent "cavity collapse" pressures. The keel side

cavity wall washes around the vehicle and the cavity collapses onto itself

along a line just off the surface of the vehic Ie. The co llapse Une: coin­

cides very nearly to a vertical line passing the center of the vehicle base.

The collapse is accompanied by local pressures in the vicinity of the

collapse line greater than the symmetric case. This is to be expected

since the energy due to cavity collapse is now concentrated Cilong a line

rather than over the surface of the vehicle.

At initial impact angles greater than about 10° ,the maximum preSSUl'"2S

and accelerations due to cavity collapse begin to decrease. This is

primarily due to the fact that the collapse line described above retains

the characteristic of coinciding with a vertical passing through the cen­

ter of the vehicle base•. But at the higher impact angles, the vehicle is

at a large angle with respect to this vertical at cavity collapse so that

the energy source of cavity collapse is more removed from the surface of

the vehicle. Another factor reducing the cavity collapse pressure at the

higher impact angles is the lower penetration depth at cavity collapse

which reduces the hydrostatic restoring forces on the cavity walls.

5-6

5.3 Maximum Penetration

After cavity collapse the vehicle continues to penetrate, but at a

continually decreasing rate, as it loses momentum due to the combined·

effects of hydrodynamic drag and bouyancy forces. With hydrostatic press­

ure in the neighborhood of the nozzle exit increasing with increasing

depth, water again flows through the nozzle into the com1:>ustion chamber.

Chamber pressure rises until the time of "maximum penetration", which

is attained about 0.6 sec. (Model scale) after insertion. At this time,

the farthest aft point on the vehicle centerline reaches its maximum

depth. For reference, maximum penetration depth is 60 to 70 ft., full

scale, for zero pitch attitude and horizontal velocity at impact, and

vertical velocities of 80 to 120 fps for the configuration with nozzle

extension. For the short nozzle tonfiguration, maximum penetration

depths are slightly less but only because the reference point is the

skirt rather than nozzle exit plane.

5.4 Rebound and Slapdown

After the vehicle has lost its penetrating momentum~ bouyancy forces pre­

dominate. For low effective impact angles (a - 6 ~ 0), the bouyancy

forces will cause the vehicle to "rebound", Le., the axial velocity

will reverse direction and the vehicle will return along its original

entry path for some distance before pitching over and "slapping down"

on the water surface. For moderate or high effective impact angles,

high pitch rates are induced during the initial impact phase and slap­

down occurs while the C.G. is monotonically approaching the water. In

the latter case, maximum penetration may be reduced to the order of 30

ft.

5-7

During this "slapdown" phase, 'a sharp pressure pulse runs up the cylin­

drical body of the vehicle as keel penetrates the free water surface

at progressively more forward locations. This p:t;"essure pulse takes on

maximum values at a point about one-third body length from the nose.

At the same time, since the cylinder is driven into the free surface

of the water more or less broadside, a cavity is formed circumferen-

tially about the cylinder. The circumferential location of the water-

line defining the wetted (loaded) portion of the cylinder varies with

axial position along the body, moving from the keel at the spray root

location to a position 90° from the keel a short distance aft. Its

location along the remainder of the body is effectively unchanged.

Since the waterline geometry varies with time, so does the pressure

distribution and associated load over the wetted portion of the cylinder

defined by this boundary. The separating flow responsible for the lateral

cavity collapses rapidly on the vehicle, but with relatively low collapsing

pressures as collapse points are at very shallow depths. Slapdown is

considered complete when pitch rotational velocity goes to zero as a

result of decreased inertial forces and increased bouyancy forward of

the vehicle C.G. The final rotational motion is quickly damped out,

and the vehicle assumes its equilibrium position. Although some water

has been taken on board, it floats in an approximately horizontal flota­

tion attitude. Thereafter, vehicle motion is limited to bobbing in res­

ponse to perturbations in the water surface, and the water impact is

over.'

5-8

1.40

1.20

1.00

Bo

60

40

20

o

./'_ 1uttie..l contact

~r- Nozzle Toe-In/~._ Me.:lt. l.'i teb Acce1. 'n

.1<-/._~ Ma:lt. A:ltial ACcel'n.

,'" slapdo'Wn t3

~./

\;11I~..c::>

VH

u

~.

APPROACH INITIAL CONTACT

T =0

FIGURE 5-2. SRB WATER IMPACT DYNAMIC EVENTS

MAX. PITCHACCELERATION

T = .02

VII........

MAX. AXIALACCELERATION

T = .03

NOZZLE- SKIRTANNULUS STAGNATION

T = .06

FIGURE 5-2. CONTINUED

CAVITYCOLLAPSE

T= .28

/"

SLAPDOWN

T = .50

~.

REBOUND

1U1'Il-'Ir-J

MAX. PENETRATION

T = .38

FIGURE 5-2 CONTINUED

...

0,6=10°

100 FPS, VH = 0, 8 = 0

100 FPS, VH(b) Vv

(a) Vv

VII

I-'l"..)

FIGURE 5-3. CAVITY DEVELOPMENT AND COLLAPSE

SECTION 6.0

SCALING RELATIONSHIPS

Scale model testing of a prototype vehicle entering a liquid (water) from

a gas (air) requires the simultaneous matching of many non-dimensional

parameters for a complete simulation of the dynamics of entry. For the

configuration and entry conditions of interest here, the most important

parameters are the vehicle density relative to the liquid density (M/PI

L3),

Froude number (F = vol v!Li), and Euler number (E = p/pV2). Matching of

these parameters along with geometric and mass distribution similarity can

be accomplished simultaneously in scale model testing in water with ambient

air pressure reduced by the scale factor, A = LM/Lp. The resulting rela-

tionships between the various model and prototype physical quantities are

summarized in the table below and are referred to cumulatively as "Froude

Scaling",

Physical Quantity

AngleLengthAreaWeightMoment of IneTtiaTimeLinear VelocityAngular VelocityLinear AccelerationAngular AccelerationPressureForce

6-1

Scale Factor

('Hodel )

Prototype

1AA2

A3AS

-rAVAl/Jr'

1l/AA

A3

Other parameters which involve such effects as air and water compressibil-

ity,body temperature, and body flexibility are expected to have little

effect on loads (pressures, forces and accelerations) .and were not simulated.

Cavitation number, ~ =

parameter although it is

Pa - Pc

~ Pw V2

matched

, is not expected to be an important

when testing at reduced ambient pressures.

The role of gas to liquid density ratio, PgIP1, is not fully un~erstood

at the present time but it is indicated by Waugh, Ref. 27, that the gas

density ratio should be matched in order to model the effect of gas dynamic

pressure, ~PgVg2. The results of Waugh are based on prototype torpedoes with

various head shapes at entry velocities of 400 fps as compared to 80-120 fps

here, and a maSS density of 43 lb/ft3 as compared to 11 lb/ft3 for the SRB.

Waugh also drew his conclusions from comparisons of trajectories and cavity

shapes, whereas we are concerned here primarily with the effect of gas density

scaling on maximum cavity collapse pressures. Except for air entrainment,

Appendix B indicates Froude and pressure scaling are the prime require-

ments.

Although Froude scaling is generally accepted for modeling of water entry, no

previous testing had been conducted which would establish Froude scaling for

configurations and entries typical of the SRB. A test program was conducted,

therefore, to verify Froude scaling using a Titan IIIC 120 in. SRB and a

12.5 in. scale model.

Figures 6-1 through 6-8 present comparisons of 12.5 inch and 120 inch dia-

meter scale model data. These comparisons are necessarily limited to

nozzle and slapdown pressures for five entry conditions because of the hi~l

instrument failure rate in the 120 inch diameter model tests, the nccelero-

meters were inoperative for all drops and approximately 1/2 of the' other 011-

line instruments were damaged or destroyed on each drop. For the I'rC8t'ntc<!

comparisons, the 12.5 inch data pressures and times were sea led to 120 i 11l'h

data using the Froude scaling relationships.

6-2

Figure 6-1 shows the maximum nozzle· preSSl,1res for Vv = 40FT/SEC at () == 10°,

20°, and 30°, and for Vv = 60 FT/SEC at B = 10° The data presented are

peak values for 120 inch data and 10 millisecond average values forlZ.S

inch. The aft nozzle pressure, No. 42, Compares well for all conditions,

the throat pressure, No. 41, has a tendency to fall off at the higher im­

pact angles.

Figures 6-2 and 6-3 show time history overlay tracing oJ nozzle pressures

for Vv =: 40 FT/SEC and () == 10°. The upper plots on each page compare 120

inch data with 12.5 inch data taken at Pro = 14.7 psia, the lower plots

present the same comparison with the 12.5 inch data taken at Pro = 1.53

psia. The first figure, 6-2, presents true value data for both models and

the second figure, 6-3, presents 10 millisecond average data for both models.

Figures 6-4 and 6-5 show similar plots for an entry coridition of Vv = 60

FT/SEC and f) = 10°. With the exception of the maximum pressure value at

the throat, the 120 inch data compares very well with the 12.5 inch data

taken at Pro = 1.53 psia. The appearance of the 120 inch scale throat press­

ure, D2l, indicates that it may have been driven into the car~ier frequency

band edge on the data tape and folded down. This phenomena has been en­

countered on other test data when the data system vqltage controlled os­

cillators are not tuned to their center frequency and the transducer puts

out a high signal level. Referring back to Figure 6-1 ,for the impact con­

ditions of Vv = 40 FT/SEC and f) =: 30°, the th~oat pressure D21 reads 72 psi.

It is expected that this pressure would increase at lower impact angles for

a given vertical velocity. Also the widely separated double peaks on D2l

in figures 6-2 through 6-5 are typical for high impact angles but were not

observed on other data for f) =: 0° and 10°.

6-3

Figure 6-6 presents comparisons of primary slapdown keel pressures for

the 12.5 inch and 120 inch scale models. The data shown is peak value 120

inch data and 10 millisecond average 12.5 inch model data. Figure 6-7

presents time history overlay tracings of peak value slapdown pressures

for the two models. Figure 6-8 shows the same comparisons using 10 milli­

second average data for both models. The 12.5 inch data is generally

higher at the maximum value but it compares very well over the time history

of the measurements.

6-4

o 0.1. 0.8 1.2

DISTANCE AFT OF NOZZLE THROAT "V X D

12.5 INCH MODEL DATA ARE SCALED T9.120 INCH MODEL VALUES

CJ 12.5 INCH MODEL DATA

o ,go IN.CH MODEL DATA

~

L~VV = hO FT SEC ~ V - 60 FT GECv -

8i= 300j '\ 8i= 100

60 '\0 60 "\0 0L...J L...J

(f) '\ ~Q.,

\~[J ~

~ hO '\ ~ hO0

:::> :::>(f)

~(f)

(f) (f)

~ ~Q., Q.,

~ 20 EJ '\ :§20

N NN N0 0z z

o 0o O.h 0.8 1.2

DISTANCE AFT OF NOZZLE THROAT -v X D

60

~~ hO:::>(f)

~Q.,

~ 20KNoZ

o

Vv = hO FT SEC

8i = 10060

o

Vv = 40 FT SEC

8i= 200

DISTANCE AFT OF NOZZLE THROAT "V X D

oo O.h 0.8 1.2

oo O.h 0.8 1.2

DISTANCE AFT OF NOZZLE THROAT ~ X D..J..._~. _

FIGURE 6-1 COMPARISON OF 12.5 INCH AND 120 INCH DIAMETER MODEL PEAK n-TERNALNOZZLE PRESSURES

6-5

RFiPtt(1)UCIBILIIY OF THE0RIGlli"AL PAGE IS Pronf?

vv-

12.5 INCH MODEL DATA ARE SCALED TO 120 INCH MODEL VALUES

- - - - - 12.5 INCH MODEL DATA

120 INCH MODEL DATA LO YT SEC

leO -- ,- 120

.5o

oo

o

Pro = Ill. 7 PSIA Pc 1!.L.7 PSIA

0 21.. '-' 80 80- -Cfl Cfla... a...I - I

~ ~:::J :::JtJ) tJ)tJ). tJ)

~ ~ D230..., hO 0... !LO

hI

IIHE ".." SECONDS IIHE ~ SECONDS

oo0.5o

o

120 120

Peo = 1.53 PSIA Pw 1. 53 PSIA

0,0

80 '-' 80l-' tJ)tJ)

~~NO, hI a...0... II

~ "~

I :::J

55 ,I tJ)

Ii tJ)m

~~ !.LO , I a... hOQ..,

D2":J

TIME "'J SECONDS TIME -' SECONDS

1FIGURE 6-2 COMPARISON OF 12.5 INCH AND 120 INCH DIAMETER MODEL INTERNAL NOZZLE PRESSURES

(PEAK VALUES)J

6-6

I---I 120-"

12.5 INCH MODEL DATA ARE SCALED TO 120 INCH MODEL VALUESI

----- 112.5 INCH MODEL DATA

--~ 1120 INCH MODEL DATA

120

......

. 0.5

. Pcp = 14.7 PSIA

oo

~: , .(/); '80p-<'I : :

g::j::=>tgs,g::j. !

, P-t: j

, ,40

0.5

14.7 PSIA

~

,../.o.~~......,,-+---------

o

G' 80'H{f.lp-<I i

~l~If.l

re 40i

.TIM,E ...., SEQONDS .,I

TIME ,... SECONDS

.L

··J· 120 •I •.:----120

INTERNAL NOZZLE

TIME ,... SECONDS

, PCXl 1.53 PSIA

o,--- ':,0'~~~---------

c!) •.

--H --'180.--(/) .p-<I .'

g::j .c .,;,

85(/) -- .. - ., ...

g::j "p-<---' 40 --

,

r

j.

1

i

." +

... i

,,... J -~_ ••.. ~,i. •._._~_!,..._

I

i P CXl 1. 53 pSIA 1I

;-;rr;o. 41

, . I \'. . \, .. '''Y--I

'0,'!" i~T'

i 'i iTIME ~ SECONDS.-1------·" .. , · ..-~r--- ---.,'- -~ .. -.,'I ' : ;.

_L_:, ,, !

o :.~~'3iIJ--'--~_---'-~,...-­0.5

6-3 COMPARISON OF 12.5 INCH AND 120 INCH DIAMETER MODELPRESSURES (10 MILlSECOND AVERAGE)

.__.. -'- ~ __L ,J.:"':L !-:..l'. ..: -i."L, 1_" ..:,'... ,.1:.. I.

6-7

,'fI·

FIGURE

I... __ J,

Vv tY I!·'rr/SEC

12.5 INCH MODEL DATA ARE SCALED TO 120 INCH MODEL VALUES

----- 12.5 INCH MODEL DATA;

120 INCH MODEL DATA

_I 120: -120

Pro = 14.7 PSIA

~H 80:~I

~,

55(I)

~P-1 40

0.5

D23

o~~----------o0.5o

o

TIME -v SECONDS TIME IV SECONDS

o -,L.oj=.1oClL_......... ...--_

0.5o

120 ' 120,~

Pc.o 1.53 PSIAI' - P.n 1.53 PSIA

I'

':~ 'VNO

•41

~

H 80', .

H: 80'(I)

I'(1)-

P-1 P-1I

"I

42~ I - D21 ~:::::> 55(I)(I) (I)

~ 40~

P-1 P-1-40'

TIME 'V SECONDS '.--, ,,~.,-,

TIME "'" SECONDS

. ~ .I

··l.- ~- ..--FIGURE 6-4 COMPARISON OF 12. 5 INCH AND

PRESSURES (PEAK VALUES), \ 'T' I '

.... --~--... ." ;.

_.

120 INCH DIAMETER MODEL INTERNAL NOZZLE

6-8

12.5 INCH MODEL ~ATA ARE SCALED TO 120 INCH MODEL VALUES

------ 12.5 INCH MODEL DATA

i 120 INCH MODEL DATA Vv ' (IJ Y'rh:;E:c

120 120

14.7 PSIA

iN'i' 4~;

',-"" --_....-""~

oo

Co?H 80'i£I'

f)3::=>(I).(I):

f)3P-! 40

D21 .

iND. 41

".--'"""-- ............. .....

14.7 PSIA. !

I,,/

"./

o

40

o

80

TIME '" SECONDS TIME'" SECONDS

120 120 REPItODUCtBILITY OF THEORIGINAL PAGE IS POOR

: Pen = 1. 53 PSIA P<Xl = 1. 53 PSIA

oo

t\:VNO•

411

\ .

,..~ ~

.....

.~ 80(I)P-!I

f)385(I)

~. 40

o 100.c;;;:L _

o 0.5TIME'" SECONDS TIME '" SECONDS

.~_.. • ~ ~__ • ._. •. __ • _ .••.. '. __---' _. _ __ ••• •••" __ _ h

FIGURE 6-5 COMPARISON OF 12.5 INCH AND 120 INCH DIAMETER MODEL INTERNAL NOZZLEPRESSURES (10 MILlSECOND AVERAGE)

6-9

., .. 12.5 INCH MODEL DATA ARE SCALED TO 120 ):NCH·.MODEL VALUES.;1

. ~I' ,0. j i2:~ 5 INCH 'MODEL DATA

, b. ~ 120 INCH MODEL DATA

I, ....

1. 0 . , 2.0 " 3·0 i • 4.0.. DISTANCE AFT OF' NOSE ~ X/D

Vy "" 60FT/SEC

(}j:= 30°

Vy = 4u FT/SEC

, OJ= 30°

C:l "~1 40P; ... ::'

L.~.~:. ,

gs',.~OI;l:-~ ....P; ..

..... -.H(i:l.

~:, o :~,.....-----------------,.;.-.--------, 1.0 2~0 3~0 ! 4.0

::DISTANCE AFT OF NOSE,,y X/D

Vy = 40 FT/SEC

4.0

,,,

'",

I'"~ "i ....... ~.~•• ," .:~, OJ "~j:'.: l .!' :. .. ~ __ ....:.. ~..:_"i

COMPARISON OF 12. 5 "INcH'AND 1io' INcif DiAMETER MQDItL _P_EAK SLAPDUWNPRESSURE

I; ;1:·

, ,C:l' """,,~. 40 '

P; ,::'::,

,~ :, .:: .

~i.' .~' :'i:gs. 20 ["~' '

P; ,,,

~!:~,.~,;i,:~<J;

o il--~_.,.._-_-~-------------:.-->: . 0" i~o::1 '2.0 :" 3'~'6 :

i o. ; !

DISTANCE AFT OF NOSE,..., X/D

,. FIGURE 6-6

6-10

12.5 INCH MODEL DATA ARE SCALED TO 120 INCH MODEL VALUES

- - - - - 12. 5 INCH MODEL DATA

120 INCH MODEL DATA

-I

75 ' I 40 FT/SEC75

I Vv"" vv-= 40 FT/SEC

B'= 30° 8i= 20°'. I .'!

14.7 PSIA! p -= 14.7 PSIAP ""e>i co coHitf.l'

50e>

50!=Lt'

•H·tf.l

1 .~NO. 17 !=Lt

g§ , '. .~

:::::>. II~tf.l II

tf.l II :::::>g§ tf.l

I tf.l [NO. 17!=Lt I ~25 P-< 25

J\ DB

0 o ...""

0 0.5TIME roJ SECONDS TIME rV SECONDS

...__..... ~ ...;._--.l. ... ._ .. __FIGURE 6-7 COMPARISON OF 12.5 INCH AND 120 INCH DIAMETER MODEL PRIMARY SLAPDOWN

PRESSURES (PEAK VALUES)

6-11

12.5 INCH MODEL DATA ARE SCALED TO 120 INCH MODEL VALuES

~_ .... _- 12.5 INCH MODEL DATA

--- 120 INCH MODEL DATA

75Vv c=: 60 FT/SEC

0'"8 ·=- ~()I J

Pel) = 14.7 PSIA

Vv'" 6(\ tllT/~~EC

8j cc 3lP

Pco = 1.53 PSIA ,

01 0HH: 50 CQ 50f£ P-l

2 l ~ ,

~!~

I~No. 17

17 :=> I,CQ I ,iCQ

CQ'~ ~' \

~ 25 P-l 25 t \I \I,

I II ,I ,

°I 0', r

° 0.5 0 0.5-,TIME'" SECONDS ;TIME ,... SECONDS

°oo

75 :75

Vv c= ho FT/SEC ,vv."" 40 FT/SEC

8i -= 3°°, 8i ~c)Oo

0 Pco -- 14. 'r PSIA 0 Pco = 14.7 PSIA,HH 50' CQ 50CQ'P-l P-l

2 1

~ rNO•

17~,

:=> gtoto to'~ '1 ~ 17P-l. 25 P-l 25:

TIME ,..., SECONDS TIME '" SECONDS

i

_.... . .. ._.. _'. _ ..-L. ,_. .. .__.._~.~., _FIGURE 6-8 COMPARISON OF 12.5 INCH AND 120 INCH DIAMETER MODEL PRIMARY SLAPDOWN

PRESSURES (10 MILISEmND AVERAGE). I ' ','

6-12

SECTION 7.0

DATA ANALYSIS

Typical plots of the drop test data are presented in Figure 7-1. Superim­

posed on the time histories in the figure are indications of the times of

the various dynamic events characterisizing the impact, as described in

Section 5.0. As described earlier, the models were fabricated to be essen­

tially rigid bodies. Nevertheless, they were not complete rigid. As a

result, there waS some minor dynamic response of the structure, excited

by the impulsive loads of initial impact producing small oscillations

in pressures and accelerations ..

Since the elastic properties of the models were not to scale, instanteous

values of the data subject to these high frequency oscillations cannot

necessarily be taken at face value, as they do not accurately reflect the

hydroelastic response to be expected of the full-scale vehicle. At the

smne time, it must be remembered that the primary purpose of the model test

oata is to serve as a basis for generating full-scale loads for SRB struc­

tural design, and the stress analysis methods to be used in formulating

that design are based on a static analysis. Therefore, the dynamic values

of pressures and accelerations acting on the model during water impact can­

not be used directly and must be replaced by equivalent static values which

will produce stresses in the supporting structure equal to the maximum

values actually developed by the short-duration dynamic loading.

7-1

The stress developed in a structure supporting a short-duration dynamic

load is not only a function of the magnitude of the applied load, but it

is also strongly dependent on the duration over which the load is applied.

This duration defines an as:ociated frequency. Depending on how this fre­

quency compares with the natural frequency ·of the structure, the dynamic

amplification factor will be greater or less than unity. That is, the

stresses induced in the structure by the actual dynamic load will be greater

than or less than those that would be induced by a load of the same magni­

tude and distribution applied for an extended period of time.

A method for determining the equivalent static load for a given short­

duration dynamic load, presuming the supporting structure can be repre­

sented as a linear, elastic system with one degree of freedom, is given

in Reference 23. Using this method, equivalent static values were deter­

mined for typical short-duration pressure pulses developed on the model

during water impact. At the same time, the actual pressure-time histories

were averaged by computer over various averaging time intervals and re­

plotted. The calculated equivalent static values were then compared with

the magnitudes taken on by the same pressure in the time-averaged plots.

The comparison showed that equivalent static values for the pressures and

accelerations developed on the model during water impact could be approxi­

mated by reading 10 millisecond averages of the original data. Therefore,

in reducing the data for the model tests, 10 millisecond average values

were read for all quantities with the exception of cavity collapse data.

The pulse period for cavity collapse is of the same order as the case

natural period for the first ring mode and actual peak values were used

for this event.

7-2

7.1 Initial Impact

Nozzle Toe-in. Initial contact by the vehicle with the liquid free sur­

face was detected by the accelerometers. All registered an instantaneous

displacement from their free-fall positions at the moment of contact. The

time of nozzle toe-in was then given by the spike in nozzle external press­

ure immediately after initial contact (Figure 7-1). Only a limited portion

of the nozzle extension is wetted at this time, and only one transducer

read non-zero pressure. Therefore, the precise boundary of the wetted

surface and distribution of pressure over this surface could not be deter­

mined and had to be assumed. It was assumed that only that portion of the

nozzle extension not shielded by the skirt from relative flow due to the

horizontal component of velocity was wetted (Figure 7-2). The pressure

associated with this flow was then taken to be constant along the ¢> = 0°

meridian and to vary circumferentially with the cosine of the ray angle,

¢>. Flow separation (zero pressure) was assumed at the nozzle exi.t plane

or at ¢> = :t"90°, whichever was encountered first by the individual stream­

lines of the presumed flow.

Maximum Pitch Acceleration. This event was detected by all three pitch

accelerometers. By definition, the time for this event is taken to be the

time at which the value of the pitch acceleration reaches a maximum. Due

to the elasticity of the model structure, the time indicated for the event

by the three accelerometers was not always precisely the same; under cer­

tain impact conditions, the indicated time varied by 2 to 4 milliseconds.

Therefore, the output of the accelerometer located farthest aft, and

therefore closest to that portion of the vehicle over which the impact

7-3

loads were applied, was selected as the reference for determining the

time of maximum pitch acceleration (Fig. 7-3).

The nozzle and skirt are only partially wetted at the time of maximutll

acceleration, and since the number of pressure transducers installed

in this region was limited~.a precise description of . the wetted boundary

was not obtained. Therefore, for purposes of evaluating the loads, the

boundary was prescribed by a rather arbitrary interpolation between

wetted and unwetted transducer locations. Since only one transducer

on the skirt and one on the nozzle were wetted along the ~ = 00 meridian,

pressures along the wetted portions of the meridian were assumed constant.

Two transducers measuring nozzle internal pressure along the ¢= 1800

meridian gave non-zero and unequal readings, so the longitudinal distri-

bution of pressure along the meridian was assumed to vary linearly.

Based on the results of Ref. 4, the circumferential distributions were

assumed to vary with the cosine of the ray angle, as described in Figures

7-4 through 7-6.

Nozzle and skirt pressures were read at the time of maximum pitch accelera-

tion for all tests. With actual impact conditions (VV, Va, ()) measured

from the photographic data for each test, the resultant velocity, U and

effective impact angle (ex - ()) were calculated by,

U = JV'r,z + va:2

(ex - ()) = tan-l (~) - e

pThe equivalent non-dimensional pressure, was then calculated for

~PU2

each measured nozzle and skirt pressure and plotted as a function of

7-4

(a - fJ). For each measured quantity, the result should be a family of

curves with VV, %., or 0 as parameters. However ,due to experimental

error, the plots exhibited considerable scatter, and the parametric

dependence could not be discerned. Nevertheless, a mean curve was easily

drawn. Similar curves were constructed for axial locations coincident

with nozzle throat and nozzle and skirt exit planes by cross-plotting

the non-dimensional curves for the pressures at the transducer locations,

extrapolating and replotting. Since given impact conditions dictate cor­

responding values for U and (a - () ), these non-dimensional curves then

yielded nozzle and skirt pressures at throat and exit planes for any given

set of VV, VH, and (). Given the matrix of full-scale impact conditions

of interest, the pertinent nozzle and skirt pressures required for quan­

titative definition of the pressure distribution over the wetted surface

were then obtained directly from the curves. They were later carpet

plotted as functions of impact conditions (Fig. 7-9).

The pressures were integrated over the surface of the vehicle to give

the resultant force in the direction of the vehicle axis, the resultant

force normal to the axis in the pitch plane, and the associated pitch

moment developed about the C.G. Vehicle mass and pitch moment of iner­

tia were used to calculate axial, normal and angular accelerations at

the time of maximum pitch acceleration (Figs. 7-11 and 7-12). Axial

load, shear and bending moment were then calculated as a function of

vehicle station. (Fig. 7-13).

Maximum Axial Acceleration. The time for the maximum axial acceleration

event is defined as the time at which the value of the axial acceleration

reaches a maximum. The event was detected by the axial accelerometers.

7-5

Generally, there was very little di££erencein the time indicated by all

three accelerometers. However, in those cases in which there was appreciable

difference, the accelerometer located farthest aft WaS used as the

reference.

At the time of maximum axial acceleration, the nozzle is flowing full and

an appreciable amount of water has entered the nozzle-skirt annulus. There­

fore; the wetted surface and pressure distribution over that surface are

relatively we ll-defined. Measurements indicated that the pressure acting

on the bulkhead and skirt internal surface was essentially constant. Press­

ure acting on the nozzle internal surface was greater at the throat than

at the exit plane, varying linearly with axial distance between the two

locations. The nozzle external surface was not appreciably wetted, so the

external pressure was taken to be constant and equal to ambient pressure.

The circumferential distribution of pressure was assumed to be axisymmetric,

based on the results of Ref. 4, so the pressures at maximum axial acceler­

ation were taken to be independent of angle ¢. (Fig. 7-10).

The data reduction method for the maximum axial acceleration event was

identical to that described above for the maximum pitch acceleration event.

7.2 Cavity Collapse

Cavity collapse is signalled by a sudden increase in external case and·

skirt pressures, and depending on the effective impact angle may result

in large pitch accelerations. This event was detected by accelerometers

and pressure transducers for every test condition except for a few at the

highest effective impact angles for 120 ft/sec vertical velocity.

7-6

For the "typical model test data" of Figure 7-1, cavity collapse occurs

at about 0.3 second after impact. The tail pitch accelerometer (EP007)

goes from a pre-cavity-collapse quasi-steady level of +2 g's to a -1 g

peak in about .02 seconds, and quickly returns to a post-cavity-collapse

level of +1 g. At the same time, peaks are noted in the skirt external

pressure (D0026), skirt internal pressure (D0028) and the nozzle internal

pressure (D0025). This test condition corresponds to a rather high effec­

tive impact angle (a - () = 32°) and cavity collapse does not result in

severe loads. The +2 g tail accelerometer reading before cavity collapse

is due to the fact that the keel centerline is wetted, i.e. the cavity

does not envelope the vehicle, from just after impact through the oomplete

entry.

Cavity collapse loads were found to be primarily a function of effec­

tive impact angle, ct- () , but for convenience are first discussed as a

function only of pitch angle for zero horizontal velocity conditions.

For a pure vertical impact, cavity development and collapse is symmetric

about the vehicle centerline and results in sudden increase in pressure

from zero to about 5 psig (model scale) over the aft 2 to 3 diameters of

the vehicle. The cavity shape and resulting maximum pressures on the

keel and lee meridians at cavity collapse are illustrated in figure 7-14a.

Maximum cavity collapse pressures are encountered at (a-e) ~ 10°. For this case

the cavity envelopes the entire vehicle below the water surface until maxi-

mum cavity size is attained. The cavity collapses aSYmmetrically with respect

to the vehicle but axisYmmetrically with respect to a line just off the lee

7-7

side and has the typical shape and resulting pressure distributions as shown

in figure 7-l4b. Maximum pressures on the order of 15 to 20 psig, model

scale, are generated on the lee meridian. As illustrated, a large portion

of the keel side is wetted at cavity collapse whereas the lee side is

wetted over a length somewhat less than fora - e= O. At impact angles (0- e)

greater than about 10 degrees, the cavity collapse presSures and loads

decrease for the reasonS discussed in sectibn 5.2.

The primary test upon which the loads analysis of this report are based

is the P-015 test, conducted at ambient atmospheric pressure, and simulated

entries with various horizontal velocities, vertical velocities and pitch

angles at impact. This test yielded keel pressure distributions and total

loads (accelerations) at cavity collapse for the full range of expected

entry conditions. Lee side pressure distributions were obtained in test

P-029, also an ambient atmospheric test, but horizontal velocity was not

simulated in this test. Thus the lee side pressures had to be estimatedfor horizontal velocity impact conditions.

Estimates of the lee side pressure distributions for conditions with

horizontal velocity were made using the known total normal force and moment

(from accelerometer data) and keel pressure distribution, lee side wetted

length (measured from underwater camera pictures), and estimates of the

circumferential pressure distributions. A balance of applied pressure

loads and inertial reaction loads then yields the lee side pressure load.

The lee side pressure load was then distributed over the above wetted

length with a lee meridian pressure distribution similar to those measured

for zero horizontal velocity. The effect of on-board water was accounted

7-8

for in the load balancing by assuming that the nozzle and skirt were full

of water but that it was only 50% effective in reacting the applied loads.

The reduction in effectiveness was used to account for the fact that this

water is not fixed to the vehicle but is free to flow out of the nozzle

and skirt.

The circumferential pressure distributions from the base of the vehicle

to the lee side wetted length are based on previous tests of a 12.5 in.

model of the 156 inch-diameter configuration tested at atmospheric and

scaled ambient pressure at the Naval Ordnance Laboratory Hydroballistics

Tank. Circumferential pressure distributions were measured at two stations

near the base of the model. The cavity ·collapse distributions were found

to be very similar at all significant test conditions. The keel side

pressures were found to be very nearly constant from the keel to the side

meridians. From the side meridian, the pressure rises to a maximum at

the lee meridian. All of the distributions could be represented quite

closely as

P = Po + Kc (P180 - : Po)

where Po is the keel pressure, P180 is the lee pressure, and Kc is an

emperic factor derived from the data and shown in Figure 7-17.

Forward of the lee side wetted length the circumferential pressure distri-

bution is taken to be of the form

P = Po ~ [ 1 + cos (

where ~wis the angle from the keel meridian to a wetted line drawn between

the keel and lee side wetted lengths and may be expressed as

7-9

~ =w,.;1

cos

7.3 Maximum Penetration

Maximum penetration was determined through analysis of high speed motion

picture data recorded during the model test programS. These films were

viewed with a Vanguard Film Analyzer and the relative position of a point on

the model was tracked on successive frames from shortly before impact

until the model was obscured by the water spray. Time and the x,y, () model

cOQrdinates were then processed in a computer program which calculated the

horizontal and vertical position and velocity of the model nose, e.G.,

and tail during water entry.

The reduced photographic data was examined and the point of maximum pene-

tration selected: The model depth and pitch angle at maximum penetration

were smoothed and carpet plotted as a function of impact condition.

7.4 Slapdown

As discussed in Section 5,slapdown is defined as that phase of water

entry where high pitch rates induced by the initial impact and/or unstable

buoyancy forces rotate the vehicle to pitch attitudes where the keel

meridian of the forward portion of vehicle is rapidly entering the water.

The vehicle e.G. is generally at or approximately one diameter below the

water surface during this phase of water entry, the pitch angle is at 50

to 80°, and the instantaneous center of rotation is near the vehicle base.

This corresponds to keel meridian locations up to about 4 diameters from

the nose penetrating the water surface at high velocities. High local

7-10

pressures and forces are generated which eventually reduce the angular

velocity to zero and the vehicle settles to a near horizontal floating

attitude~'

Slapdown occurs over a finite time period with time varying ,pressures

and accelerations acting on the vehicle, ,and there is no specific time

at which structural loads are obviously at a maximum. In order to inves-

tigate the variation of structural loads with time during slapdown, press-

ure distributions were integrated over the vehicle to obtain applied load

distributions and the inertial reaction load distributions were calculatedI

for several times during slapdown. The time points selected fo~ slapdown

load analyses were keyed to the times at which the keel pressure measured

at selected transducer locations was at a maximum. Results of these analy-

ses showed that keying the load analyses to maximum pressure times at

transducer locations D0003, D0005 and D0006 (Figure 7-21), would yield

three time points, one of which would always correspond to very near maxi-

mum values of local pressure, and/or shear and bending moment. Structural

analysis at these three times (tl, t2, t3, corresponding to maximum press-

ure times measured by D0006, DODOS, D0003 respectively) should therefore

give near maximum st!esses for any given impact condition.

The slapdown phase is illustrated by the typical model test data and cor-

responding full scale trajectory shown in Figures 7-21 and 7-22. Initial

full scale impact conditions for this run are: Vv = 84 fps, VH : 34 fps,

(J = -8.9 deg. The pitch angular velocity increases rapidly to about 19

deg/sec during the initial impact phase and then gradually increases to

7-11

about 45 deglsec until cavity collapse occurs at t = 1.0 sec. Priorto

cavity collapse the keel side of the vehicle beneath the water surface

is exposed to hydrodynamic pressures while the lee side is in a cavity

at near ambient pressure, causing significant tip over moments. After

cavity collapse, both keel and lee sides experience nearly the same press-

ure and the pitch angular velocity remainS constant till about t = 1.2 sec.

The vehicle C.G. penetrates the free water surface at t = 1.3 sec at a pitch

angle of -50 degrees, and slapdown pressures on the keel side above the

C.G. have already started to reduce the pitch angular velocity. tI, t2

and t3 are 1.4, 1.58 and 1.78 seconds, respectively for this run as indi-

cated on the trajectory. At t3, the pitch angular velocity is down to

28 deg/sec, and is monotonically decreasing.

The tbtal vehicle forces and accelerations during slapdown are generally

of low frequency (on the order of 1 cps) and low amplitude (less than

4 g's at vehicle nose) when compared to initial impact while the local

peak pressures on the vehicle keel are high frequency and high amplitude

(see pressures D0003, D0005, D0006, Figure 7-21). The slapdown pressure

time history for a given keel pressure transducer actually appears as a

suddenly applied pressure with an exponential decay to approximately local

hydrostatic. Although the local peak pressures near the keel penetration~. ..'

location appear as a high frequency pressure pulse, the overall keel press-

ure load induces low frequency vehicle loads, on the order of 1 Hz. The

vehicle position for the above three slapdown times are illustrated

in Figure 7-23.

7-12

··~m::l:t:* r-mEEBHEB3f....r -r TT-r+- kf !I.!IX ?: ~"h A~~elera~~;n 1= -- .; I(~J--~ .... ~-l--: t - -:r-t-=f- -i/=-: - - ---- - -- =r~: =t- ~Hj.J: =;1*"1=+'-- !\ 1- -~ --- -- - '-1- - -+- T - - iT ~L - -~ - - t- - __1 I -11 t ~-r

Pitch A~~elero._~or• • - -- - - - -j~\I'; ." I -.'. - i-I. c!_ -I ---- --- r- ---, -:f(E?()07) .... i' - 11: '- - -- -- -- .... ,- '1'1- ---L -t- .... -

-I. ~ ~_: =~I-- -,l~ -~ ~ :: _' .... ~ _' .... ~ _#-~ _>: =:: .... ~ ~ ~ --_ :Ott .~ -:: -, '

Nozzle F.x~er"el

Press~r"

(DJ025)

Nozzle 1nt"r:o&1Prc.. ss .... re

(00021)

Sr.lrt Interrllili~1"~~.G..i.l"e

(:Mh:t:)

'.--........ _.... -TILLLLLIJIITLL1- --- -, .... ---- - - - --:: - - - - - ill111''-o ~ ~ '. ---- ~ -~ : ---lil~F-i~I'~:;TT!lt<r:l- -~-- ~. ~ ~~ -~ == ; -: ~ ~- -- -~-:f '-1- -!-

_ --- - -I- - -1-1- - --i~--ll- --, ,1-1- -I- -~-l -1- - -I-Ill Ii-I I

-f-I-+-HH-I- - --- ,- -1- -- .... - -- -+- - - --1,- - - - -- - -. --' - -_-- - -:.;)t_e: ~-'rc~',s'~re in p:;l€". ... - - -

:"\2-.=e':'erut;L:1 !on b'G. _ . ~ ~~ _- _. _. _ .. _.' .

RETRODUCIBILITY OF THEORiGINAL PAGE IS POOR

Cylinder BodyPresGure(DCo-J-J" )

Cylinder BodyPress _;re -(00005)

Cyl' nder I'cd:;PreSSi.lre(n 1,)-J3 \

L

: -~--_::::=~: -~:~:::~~~j:i-ti~lr ---: - -11- -+ - ,-1- - - + -I--+- - --1- - f-l-I-~--I-l-l--l--l ~-I .... I- 11-1 I t I

II--I~ - , ..l---I-L--J--t-!-._.... -- - -- n-~• _ .... - - -- ........ - - - --f- - - -- - -.... _,~lel"l,,\m t] -- --- -, -- - .... -, - ---

.... ::~ - -~ - .~~ ~- ~~ ~ ~. ~ - -- ~- -- - -~ -1\ -~~ .... -- ~ --- .... - ~ -~-~: -~- ~- -~ -- -- -:.... --- -.... - - - f- ........ -- - - .... - - - -'- - .... - - - 3--- ---- ----- -" -, --

o i"'ir.~:--r .... ' .."'" - _ •• ~ .;"J'.- .... _ .... .... Jjj~_ -11-:--1-_ = '--I- - -1- j-_f_tLl-- ~ ~ iJ f1 J

-~""""-·t-t-""""-t-t-1- - -

+++_+++_++-_+++++-_+-__+_-+-__-l-_-l--I---l-I--I-t-I---I---II-UW-I,W-I->W_ SIs pd",m t 2 =.... -I+-+-+-H

- -~- - -: ~- - -: =~ ~. =: - ~ ~ -- .~ - =-~ -= ~ - ==-- -- -~ ---, ~. -=j-l- ..

IJJJJIt;.'~--'---'---;,""••.1-!-~•.L;••-L---"---'-'-;.-i;;-•• .L-l....-I-..-L:-.L,-.I L.l......~• •~.LULLoJ•.--:-.l• ...LJ~••-,-1....Ll-l.:.l..,-l,...Ll-i,J-,.. I.',rIC lICU

FIGURE 7-1 TYPICAL MODEL TEST DATA (TEST P015-70)

7-13

NOL;L;LE PRESSURE

o EXTERNAL

The wetted surface is defined to be that portion of the nozzleextension below the undisturbed liquid free surface at themoment the skirt makes initial contact. The limits on ljl fora given value of X are then defined by the waterline, but arenot to exceed +90 0 •

NOTE: All surfaces for which pressure is not specified aresubject to ambient pressure.

FIGURE 7-2. PRESSURE DISTRIBUTION AT NOZZLE TOE-IN(WITH NOZZLE EXTENSION)

7-14

MSFC SRB WATER RECOVERY T~STP-015-7~1

E:r-

2.62.52.32.12.01.8

L.-..L-.-L..~"+-t-t-t-+'-, 'tt'-t-t-.-H-t---''-'-+-t.---+..- --++-t--. -+--t--~ ~~.H-+-:~::=:-H-+--.+4--H-+-t-+-t-t-H-I--'--_·_L_·· _··1··I I I - - 1-.. - --- - ..-- -.... --. "---.-- r~ _

TIME (SEC)

..... -. '-'._.-.- _.~ - - --- _. - .-

TIME (SEC)

1.81.7

.....T-r- .-- ..- r.~ -.-- ,- -.. r- '-- ' .. r-' _.... :-........- ----.,... .'..-., .....,-- "., !12~t··· ...._- - _. --' . . ..- -.. ---t- - -t- .-. - -- ._.._.- . . ,. ....

'--'-1'" '-of-- -- - -t-,- --f- -. _or-c. _. -- -- -.. _ __ _1,,_._ --.-t-- __ ._.. I. -._l--j-+-~-_.~I--. -- ---r--'f-'-~ -- -1- ..- _ .•.- -- -. - -- - . "- -- -- - ._-t-. -- _. - ...

10t---t----t-----e--1----t·--··t---1·--·ffiH-+-t----+t-~-t:_-++--1_-_+-·-+_I-+--+-_I·· M-·'+--_+--..-+_---4.--'+.'_1-_..-+---.1---_+-1__+_... --4._-'+'-+-+-1---+._-.+---+-_.+--+-'+-I_ t I-_..--t- ._. - -. .c .. _.-. - ._.__. . _ .._ ..'_; ._ ....•__ ._. __...••._ ._ ·1- ··-r.·

-- .• ----- -'-' .--.----------+--..-.-- -.. _-- ..._--t-.-' - "--' .-. -.--.- - ...- \

8 Lt--._'t'-' ..."-.r-f--.. :_-.r--_=~:~~ ~ =-~_.-~ ~. :~. ===.~~ _. -. - --'.-. _'- __L_1

J.r-: -.- -. --. _. _. '- -' _ -. ~ ... 1._ -- -- ..- "- ._ ....•.. -- --"- - ._- -- _.. _. --

L_

t1

9

EA

FIGURE 7-3 DETERMINATION OF MAXIMUM PITCH AND AXIAL ACCELERATION TIMES

7-15

'- _.

---------~

~------/

BULKHEAD

SKIRT

NOZZLE. !

\

I II ~- t F1----- LS

FIGURE 7-4 - DESCRIPrION OF VEHICLE AFT END GEOMErHY. (lfITH NOZZLE EXTElJSION)

'\ -I -I

--I ep,I I

-+- .I i Keel- (cf>=D°rx II

II -.. ..j

/ --'--- ---------

7-16

BULIffiEAD PRESSURE

• INTERNAL

P =Pambient = const.(

-LB < x < 0 )-lS00 <ro ~ +1800

- , -• EXTERNAL

. P = Pambient + ~ (P1 - Pambient)(l-coslj»

SKIRT PRESSURE

.• INTERNAL

P = Pambient + ~(PI80 - Pambient)(l-cosep)

P = P3 • cos eJ>

NOZZLE PRESSURE

• INTERNAL

P = Pambient + ~'PISO - Pambient)(l-cosep)

• EXTERNAL

P = P.6' • cos eJ>. (")

(P6 - Pambient )

Po = Pambient + -. ·x1N

NOTE: All surfaces for which pressure is not specified are subject toambient pressure .

.'FIGURE 7-5. - PRESSURE DISTRIBUTION AT MAXIMUM PITCH

ACCELERATION (WITHOUT NOZZLE E.XTENSION)

7-17

BULKHEAD PRESSURE

SKIRT PRESSURE

NOZZLE PRESSURE

• INTERNALP = Pambient = canst.

• EXTERNALP= Pambient = const.

• INTERNAL

P= Pambient = canst.

• EXTERNAL

P = PI • cos cf>

( -L13 < x <: u )L' - - 0. -18l) S. et S +ltk:

(-LB. < x < 0 )0- - a-180 S <p S +180

(0 < x < LF)

.-1800 s: <p ~ +180°

(LF < x < LF )V- ..,.

-900 S <p S +900

P = Pambient + !• INTERNAL

(,1'180 - Pambient)· (1 - cos ep )

-(LN~LE S x S1N+LE),-1800 $ <P S +1800 '

-(P3-P2)· (x _Iw+~)LwLE 4 )

P = PI • COB c/>

• EXT.E:RNAL

(LF S x ~ Lri )-

-900 ~ <I> S +900

NOTE: All surfaces for ~hich pressure is not specified are subject toambient pressure.

FIGURE 7-6 - PRESSURE DISTRIl3UTION AT MAXIMUM PITCHACCELERATION (WITH NOZZLE EXTENSION)

7-18

zo...,,«II: .o ~

n. •11::>oU

zwCIN...W

o

II:wQ.

«[l

I IQ.

U« Z

g~Z.Jw «CI I

~~~Q.0 0

6~"; 0

"rJciZ

'~r:-:-,TOO. . . ! . .

7-19

7--20

Max .. Pitel] Undefinedat VH ::: 0, () =- 0

iII

i

!" i

NOTE:

, . \

.,..... ,

,

II .

i I()~: -llP

(} ::: _100 '., ' ;. " I

.. l

, ' I'

! j ;

, ,;

4/n CONFIGURATION ! , ' ,: WITH NOZZLE EXTENSION .. !,.

Max. Piteh Und.ei'inedat VH == (), e 0' 0

-j I .' Ii I I I I

VARIATION OF NOZ/:,LE INTEHNAL PRE~)SURE WI'l1I IMPACT CONDITIONSMAXIMUM PITCH ACCELERA1'ION

I

I./

200

o

80

40

120II

\\I

I160

FIGURE 7-9

I I

- ,-.-- ~- ---"T J'-'-- -;--- -• • • I I •

, . '", , . ,

. .... . .~.... - _. .-... .

I

160 .... i- -

(J c= _20 0 ;'

I

II A

[J)

P-J

7- 21

BUl,KHEAD l'l{ESSURE

SKIRT PRESSURE

<t INTERNAL

p ~ PaniliientConst.

.. EXTERNAL

P = P1' canst.

NOZi'.LE PRESSURE

P2

I

• INTERNAL

P == PI canst.

• EX1'ERNAL

P ~ Pambient canst.

(I INTERNAL

e EXTERNAL

P ~ Pambient canst.

(0 < X "LF \

-1800 ;; ¢ ;: +180°J

(0 < Y < LT" \

.:.180° ~ q, ~ +lRao )

NOtrE: 1\11 [;llri'aceL'; 1';'1' vJllich pre:";Gure is not specified are Gubject Loambient pressure.

FIGURE 7-10 PRESSURE DISTRIBUTION AT MAXI.MUM AXIALACCELERATION (WITH NOZZLE EXTENSION)

7-22

. I

I'

(J = 0 0

II

,.. 1 ..

I

I

.1

(J = _10 0

jl

. ~ . ~I." ~

-lo ~e! () I

1

orP

i'Y .

I I ()I tjlI c§J 4,~\"Y -

.... I~~

j \,: i

, !

, .

----.- -- ..+.~~.- -~._.._~... -_ .. ~-""._"-~'--'~-'-."--.--"--'-"-'-~"-."'-"'_.'-""':"o·-:'-T" "1-1~-.~~._-,. ··r·--·"~·4'~_-'.'-'--" - 1'-" ," ·f.

. . . : hill CONFIGURATION . '," i '.;: .. . I''. ': ~I.~H. ~O~~L.~.~ENSION~. : .. :. <_ j: ... '. ./ ..

II·I

. - j" .

Ie = _20 0

... /

o,0

C\J

I~I

I ~()1"I

'VARIATION OF MAXIMUM ACCELERATION LEV.ELS WITH IMPACTCONDITIONS - MAXIMUM PITCH ACCELERATION

I -"11

FIGURE 7-11I ---1- I

III

III1

8

.. 10 I

U)

o

'2

~"l0,HiE-<I 6~ I .ffi~oo~

;;j. 4H,~:

~I

I!i

I

7-23

I\

!iII/.I

., j00 I

I

I

i

I.\II

... ( ... 1

I.i

I' !

~ i .

!'0~.

!

II

I. .. iI

I.I

(J T· .~~~~, .. ,II I

': b"'jI~ I~.---::'~j

, Ve'

I'j'

I. I.

I

-..-...-----..... .. '-- ... . . . --..--.' .-'---.; r-----.: "- ~- ---',-', .' ," 4/11 CONFIGURATIOIJ ,,'; ; " ;!:.

, WITH NOZZLE EXTBNSION . "

IIII

.. \,

o&

"y

I!I

Ir

I, I

() = _20 0

I

II

I

II

I

20

~,

I·····1

o

0) i~; :

1

"I~!

.1 150'

" I" 15oH

~fY~tju 10o.~

:~t3b'~ 5

oFIGURE

I

i7-12 VARIATION OF MAXDIDH ACCELJ<]{ATION LEVELS WITH IMPACT

CUNDITIONS - MAXIMDtJI PITCH ACCELEHA'rION

7-24

.... \ .. - '1. ,

II

!j

I

----_. ---'''''' •. -- - '"!"'" ~ •

: .: ~ :.'

i;I

I I.II.. 1

ISHEAR AND BENDING MOMENT ARE ZEROAT MAXIMUM AXIAL ACCELERATION

I'I'

""""1 4/11 CONFIGURATION " ,, "'. WITH OR WI'~'H?U.~c-NOZZ~ ~~~SI~N

i!; ! 1 ,

II •

. I

I NOTE:I

III, I, I

I I I .I I 1 I· i k---I-/iii I ~I;i

I i II I i I!! I I'

I( ! .L~-'-~~-Iii

: I I --t.~--:-I I Iii Ik'~11j ! 1 I I: 1-.-..:---+-1-+-1~--'---'+--

)~oo 6qo 80,0' 1v.lO I 120J [ 111!)O I 161°0 18\00

.j I L 'I ,VEHICLE STATION,IN. I ' I .. j I : •

JL. I I I I ; I,,_'1_L. - I 1-'~-~~_-rlJ_NORMALIZED SHEAn ponCE, BENDING MOMENT AND AXIAL FOHCE DISTRIBUTIONS­

MAXIMUM AUAL OR PITCH ACCELERATIONS

·5

i10i

0U)

0...~~0~0r:<4n:;

t5 -·5~U)

I\I

-l.J

()1. !)

"'.

I·'.

"[-1

N !Q c:; I.. ~~ .,/

~~.', ..Hr::::l~

II I

: 1.~) I, ,

0,~!

I

r:,-i' i0'0:;,0' 5'f..r--i .I •

IH\;::\';x: I<r;1

--'f.I-GURE, 7-13

7-25

T = .02 T = .04 T = .16 T .24 T = .34

"IN0\

Il<

~mCf.I~

g:;

TIME LOCAL HYDROS~TIC

FIGURE 7-14 QUALITATIVE DESCRIPTION OF CAVITY FORMATION AND COLLAPSE(a) NEAR-ZERO EFFECTIVE IMPACT ANGLE

T

LEE SIDE

KEEL SIDE

T = .24

WALL SLAP

LOCAL HYDROSTATIC

T = .04

~

rzJp:j

gCI)

rzJ

8:

T

'-JI

N'-J

TIME

FIGURE 7-14 CONTINUED (b) MODERATE EFFECTIVE IMPACT ANGLE

j-;--­t···

I1-,

---- .... ~-~--- .... - _.- ~

I1-'-I-,

L.. --\

"\'-

'-!.. ~.-l '

. -, --> -..... ~_.- _.' -~~-:-~,:.~:~ .~--;.----.~ -.".-,.. i

!i'-:.!-L. _J :-- - _

L_ ::-:--:--j'." ·1

-.,t

. I"

-,I.L

,CAVITY COLLAPSE RADIAL PRESSUREiDISTRIBUTIONS AT STATION 104.2

i. ~_.:

,,i

"j

-1

.:: i•. _f

"l _. ::.:t-~'::_J

r-~ ~k·~ _~~:~ L --'-

1--

:}:

. i

180

;

·7+-l-L·i:····r··,t •-t"~·:1'-~-r~l~:4rj- "

; '- .:"_L-,,~_:T':::ff:j:~;-{-~r~ttl

;-. .; -c~;':~~:E~ :f:0'cFL:l- ..tt

135

1.53 psia14.7 psia '._

, __ 1_---45

~::-c.··t,~_·.: - -- - ,', ... - ;-~- -;~~_':"~:_---':-,:---~~~iC;:1-::-:"'~ ---~. _l_.~_~: '·'jd:,;.tf' c. -:Vv - 16.97 Ft/Sec I _ ~_, _. l, .•-- : . __ . . . 1.

1.

"_._L~_J,,-~i9i ~-~()IJFiiJi~F+'-,-': ..~+c"+~h"-~~ ~~~.:~-- '~~;~-'j-t:~.~'!

o

• c. b£Y'~ .~~

o.{.I

fx4§5:'

._~~:;-

.; .. fx4--"ft'

d__"~;',T ... ,·!hJf~~rr,· i I. --- ,+'j_.'--- -. L ' -i

"

~::..

Lt:· -

~~~~l-J-:~­t::~>i- -

L

I

L'

~':";-c '-r:-' -,-. i··- -1'--' ---

L:~_!-T,:c

I--.JII

NCX)

. RADIAL ANGLE (ip') ~ DEGREES- - -,. '~_.'- ......--... ----_. -;-"-------_._.._.- .

FIGURE 7-15 TYPICAL CAVITY COLLAPSE RADIAL PRESSURE DISTRIBUTION,NOL 12.5 INCH DIAMETER MODEL

CAVITY COLLAPSE

SRM CASE AND SRB AFT SKIRT· PRESSURES

LW K, ,

x

111. PKEEL

(0=0)-----

SRM CASE

P = PULLAGE, UNIFORM

K--,--------

PLEE(121=180 0 )

INTERNAL PRESSURES

SRB AFT SKIRT

o s X S LF' -180 0 s 0 s 1800

EXTERNAL PRESSURES

CIRCUMFERENTIAL DISTRIBUTION

P = PKEEL, LW L SX S LW K, ,

KC' SEE FIGURE 111-2; -1 [2( X - Lw,L)0w = cos ( )LW K - LW L, ,

LONGITUDINAL DISTRIBUTION

SEE FIGURES FOR PKEEL & PLEE VS. STATION

FIGURE 7-16 CAVITY COLLAPSE PRESSURE nlSTRTBUnONS ­SRM CASE AND AFT SKIRT PRESSURES

7-29

, . '----~-I~-I---~-I----t~-f-~--- -~-~--- ---t-- I r----'~t=--=== - --- -- ---;j----i-- [--r---r-·--t===I=~=' == -=-~ =--:== =:- - -:=:..-t===i- ---~-.=1----l---t==;---------- - 11/1/74 CONFIGURATION __, t --- ---.-- ._--f-- I • .j

l==---=--=f==-= -j--------=:-- --~-~----~----I--·-l-u---j---t==V----I-----1--- --- . -- --------t' 1. I~- . -'- --=--t=-- --==:=== ==--=::= -==--=-=l===t:=:-=)~:-=- === -===1--.---= --==--=r=~~~~=== -- =-=.- =:=====- --=--f==1

t===- l-=-=_=-~~=- -==J= . . .=~-~ --=~~ ~~~~=-=j~=~~~h=.-~=_f=L-=== -~- -=~~~~=l~~:==f--- -~I--::-~~U==-- -===:1=---=-F-~1=~=j

'.JI

Wo

-~I' i !~

I i I+------1-;-----1

~

t -=1..:.._:~:=r::~b~--i·- '-E7 -1--::=---,-l '=l--~--l-·--l=~=:=:=-l::"=-+-=:=!~--:'I:=-t- -----r:- ..·-.L=:=ll0--=:=--I{---==t=--::-i~o:- !--I-==1===-=--- =~-=-+-=:=-=:. --===-...:=,=~r===I==j.-::=-~PD ~=Li-Nciii---~-~ :ri~~ J~is-=-C=!~~-~~= :~,~=i:=:':----! -- .:: ===r==-:---·t;==~______• ~l __ '--_~ \ / \____ ___MERI IN. ,0, __.. +_~ __ .+ . . ' I_*..__ .L ~_

-- --,--,----F'II1''="RJDIAN --- ---'-!--- ----·,··I----·-·-i-------i---i-----:-~.-:--- -I - - ;--- '---·i-----'_ --~.-_.I-:_:.-__:~r-_-'- -- JERfDIAiV-~-- =-=---- ===--l~~::---i' --; --..-_--t-:::'F==--~=-- -- l~:==-..:-l=~==-::-l::.:.~-==::-::t'====--:::I ==-, ~=.=-: ====:~;-==r::=-::::J:: -:-=---~----1 =-..- -i--.--,--.-

=1 ----:-J==-=::(-=::=:~~-::: ~:~--._FI~.~lm -1· ?-":~?-l--~~. ~~~-~-I~~~._~-~~-~---~-REssl~-~.I.S!~~.BU!~7~~Af~T~~'j _,~ . =~:~:~i=:::'::::- _- . t= !-- I

--t-----'-----I- -- -- -T--- - -- --- -1-'-' •-t-- --·-1--- ---r----:---~ -. ------1---" ----I ---I

!-~-j==I~.--·----1-'-.---1-.:'1=:::=-~I:'= -'~l-~~r~.'i~:=-_~_7-1-" .--.+-----~'.'~"'. ~t--:-.',''-f-----.. , .-' -- '! .. ----:-===:=:.=---!---==r=-; --=l---~=-l==::--_;-'-~--:·"':=:-+~-'- --- '--. --:1==.1..:-_l===L===+--~t------~--':'-I--r -----,-- ==f=! -----,-,'- ,._--: ~,.- :---I--~-" __-,. ------t--.i----

"-JI

WI-'

IL-l,:;: 5 X 5 TO THE CE~TIMETERjr).~·,:;;:; 18 X ~4 cv

KEUF'"F"El & ESSER CO.

--_.~---~-~-----~--

46 1610¥ ,,= ( ! ~l l.:. s .....

jI

Ii,,,II,I

II

i, .

I

i!III

II1I

I

, ..

I1

1

I

,. '

II

. i Ij I

j;,ji<

t<; I" Ii

II

__ _..... - I

I,I,III

, ': ;"; I

., :~Lbo-:

o=100 I / ~ fO°

I IIii' II .. I'

, .. . . .1··· I· .. -..;: ..~ -~ 1-

FIGURE 7-19

VARIATION OF PEN1'TRATION DEPTH WITHIMPACT CONDITIONS

.0

I

I.... .I.I

I- .. II

50

" - 40

.. 60

Ii \'1 .. . I

I _.. _I

I

I

30

I

II

20I

I I

·1

. I .

70'1

.1I

I. ! i

I

I

60I1 ..-

I50

40

70

I

I

iI..

iIj

I

! -.--'-r' .

7-32

II

I!

(nOII'

!I

'I;

FIGUHE 7-20 I

, ,

--'. ---iT ~--;7-

: . ", '! •

----: ~.,.-:---

, ': I

i'

, ; 4/11 CONFIGUrrATION,,-.- WITH NOZZLE EXTENSION --

20

o

-60

-20

Ii-40

I, j

II

I-I

\

II

i

-20

[

I-40II- :-60I!II

~. -, 'f -:---~-" --:-:--j_._-: ,---' ,'. . , . .

. . . ... I:::E:::

IVARIATION OF ANGLE AT HAX PENETRATION

WI'l'H IMPACT CONDITIONS

7-33

.. ~

.-...."

- --i.............•

- - I ,...... I

n

--n n -

~ " . I

I I I_J'-..1

<-Jsl zl0,

H SI81 §/,..:l

-....I 81 tr\

I 81w ~

~ MI ~IH

I I

zlo

~I~Io~I...-l

HI

I

NOTE: TRANSDUCER PRESSURE TIMEHISTORIES ARE SHOWN SHIFTEDTO THEIR RESPECTIVE MODEL BODYLOCATIONS

I II I

-I I I ....,

r--

f I I IIII

II ~

r-

1\ 1\ \J.....l

f\ - rIL

T = 0.1 SECONDS~ I I II I 1\ r I I I I I I TYP. ALL TRANSDUCERS

~CI.l~

€C

FIGURE 7-21. TYPICAL TIME HISTORIES OF SLAPDO\\TN PRESSURES

" _,1:

._- '-

_1- _'---- __•.__ . __ .,.__

"

50 I--t--+---,f---t--+~-+--+--+-t--t--t--+-t--t--t---j-t--t---t--jt-i-+-t--:t-T-+-+-t-+-j--f--f-- - . - - .__.- -- -c_ _ _ I_~. --- -- -- -- ---. _

~- - '- --- I~ --- - -- --f-- -- --- -- _. - -- -- '-- - -'- --.-' _.. _. _.--- -~ - - -- -- ~- -' -- - - - --- ._- ·-1- _1_._ . '-1_ -,--- ..•._- ._. _:c __ ·__ 1·

o tf--:J=ll~·--tll=1=tl=tf--=~'-=-J-=c:rll--=J=l=J~=~--=~-=+r=--ll-=-~-=-t:L-:-~'1='-~-~==i==+~=1~ - -- -. .-~I--f--- ~f'- - --. __ -.=t.;;.;'-I--.-:L_....-l-~r::r::.~ ---I'- 1--.,._. ~_ -- _ .:.::~ _~Io- 1 ~. . .

l-.--I---I-~_l__ p!-- ---- - >-- -- -I~--f-- ,-- --.. _- - .

........-+--I--1c:::: p l-l-l-- -- - -- -- --I--- -

50 ~-l--:::;>1--4~-I--!-++-+-lI--+--I-++-t-l-+-+-+-t--t--I--1--t--+--+-l-~-_...- .- f-­- ~~

V<.ct:icalF'usi ti on

(ft. )

°kJ-+--I--I--1--+--+-+--4--.l;-1l-t-~~+-+-++++-+-+-t-t.,.-f-'-lrr-I-+-+-t-1=---~"""-kL--I- - --f--'--~' __ -- ~- --_.-- -..-_. --. ---- -.' --" -- -.- - - r-- ""-k 1_ '.. -'-'- _ - '---' _.- -._

---=~~~~~~======~~--~---~jf')l'i :,;untalj'u::.; i.tion

(ft.)

~""- .

-:1--1---+--1--+--- -I-- I-I-"~J;:::::~~ ==-.=-=-_ -- ::::-= __~--~--~- ~ .

.. 0 ~ e-I-·- -I---- - -- .--.'

~I- -- c-- - -- i- _I~ I-- '---f- f---- - >--- -'--1--1--- ,-- -.,. --h-I----I-f-- - .-. ---1--- _.-..---- -- -- .-_. -- ~-..-- ._- "- 1- --~I-- -.-. _.. -- ..._ -- - --- ---- -'--' .. -.- - - -'- -1---- -- -- -__ .- - --. --.- ..

-

100 ~-+--+-I-+--+--II-+--+--+-t--+--+-t-t--+-!--1f--1-+-t-'-+-+-\-'-+-+---l:-+--+-+-j

..

~I- -1-- - ..1--I--I--+--I-~I-·I--f- -I--I---I---I--~I--- - -- --t--- ~---- '-l-o-h.." -I-I--- _1_ _ ...:.. _1_1__ .__ • ,- _

[,:::1-- ..- I-- -- I-I- ~I--I- -- -- .~.- _. ----

~-I-- - -K --~--I-+---l---f--'--1'--'- .- ~I-- -- -- --

f---I-- - '---I--- --- --.

~~----,---._--~----------~~--_.~-----~_._----

o l-..l-J--II-..l-_L-JL.L..J-J_l--l---!---1_L...-1--1---Ji---l--L.-1-.-,-~-1--1..-1-_~..!---J----.li...-.l-_I__ ._

VH'UcalVC'}uc:ity(L'L/:.;cc)

1----1---1-·-1--1--· 1--1-----1---11--4--+-1--·1-- -----I----l---II--I--+--I---1--\-·I---+--~---·--- .. - - -..

.J_I

llo:dzontalVdocity(nlDec)

i--I- ->-- --- -1-+-4.--l·- 1-1-- --1--+-+--+-- --- .-.-- --- '.--f-I-- -1-+--+-lI--1-+--+-f-'--+-+-t--l~+- -I---~-1-1- -- ._--~I-~

_ 20 f-I-- -- f-- -1--1::::;1;..-1- - .-

~f-_~I--I_+--+"'----J_I-I-+-+---1f--+--+-t.-_f-~ :=~C:~,=':P:~~=~ ~ :-__~:30 ~f-r;;z -~f::::L....~,--I_-_I_-+_I-4----t_--f- __ -~._F-:: -1- -...,. -·-1_1- -_. - -_. -.-

·-1- -- - _ - -- - --_. --- -.-.---~l--- _.1--.-- '--- .- .---.- - 1-.-- .-. --

.. 0 ~>--_. ---- -- -- --- -f-f--- -f---- --1-1--1--1---..- - --. -- ---- - ...---' ._- --

Fi L:'! [ f\.ngle~Jeg)

--.----+-- -<>-r-t--i --....--+--1---+--.---.--1--1---+-f-;--t-- ---t----t---t----+-~t·--;I-;-I-~ ---

l---I-----I----1 -I--I-----I---I---I--1--+'----J--1---4---I- - 1- - -f--- I-- -- - - - --

f-- ~ f--f--.--- c= ...:-;.:;::.1----1--

.. 0'-- ---- -...- --~~-_r-.--,-. --.---.---.-,--:..,----r-"-,.--;_p,--r---r------, --";"'-+---l--"'.---l_I_-.-_-__ =.~E:~ ~~_

1---~-I------1--I-----I--I---I-.I---~-1---I-_1-- .~J._o<t:::;;:;;:::::..I---'I-~-_f - --f--ll--f-+--~-- --- - ---. I-- --~~ - --l--I--I------I__I-t----t'--.,-=~_._----~f~-- - ,.- -- - .-- - c- - .-. - .-.

----::::::: --e- ~j,-.J--I---+.:...--I-- -----I----1l--t---· -.--. - - .. _.Pi tc 11 Angular 20 l-+-+,+-4=::~:t-~-~-l--+_+__+-1-~+_+-+_l_-J-~-f-++_+_l__1f__f_+_+_+_t_i

I------I-----¥---r-=-J.- --II--4--1---f'-I--I I---I-~I--·I----t--I-'----J-I---I--.-.-- --- -' -- -- -- --- -V",loci ty ~-H7q.._-+_-'-i_1__ 1-_-I_-+-_1_-1-_~1--1_,_-!~I-+--I--+--~--f--_ _ __. .._..(deg/sec) 17

111- -'--. ~-I- - - --I-I-- - -- --- --~.

01--lL4--1--1-l--l-+--+-+--JI-~4--!--+-!---JI-+-+-++-+--1-+-+-++-+--t-I-+-+--t

1.6

-I---f---I--- - -- -- -- - -- - -' ---- ---. - - .-1-----1-_+_1,_1_1-__.i_1- - -- - ..-1-----1-----1----.._1-__ -- .- :...__ - -- -. -.--1---.__1.----'1-1-1- -- '--- .-

0.2 0.4 0.6 0.8 1.0 1.2 1."o

'l'ime i'r::\ifJ Initial Contact (sec)FIGURE 7-22. TYPICAL FULL SCALE TRAJECTORY FOR VEHICLE C.G., TEST P015-70

7-35

_40

1.40

1.20

1.00

80

60

40

20

o

_20

I'~ lntttn~ contnct

/ ~07>7>1.e Toe-In

j,t'/. /~._ Ma)t.. Piteh Aecel 'n../ __..--:--Ma)t.. Axia1. Accel'n.

7-36

SECTION 8.0

FULL SCALE LOADS

Full scale water impact loads were calculated for SRB configurations as

they evolved from the initial 156 inch diameter SRB to the oarrent 5/1/75

baseline configuration. These loads cover significant loading events

from initial water contact through final settling iIi the water. A data

base compiled from scale model tests and Froude scaling techniques were

used to generate SRB loads as a function of water entry condition. This

section presents the procedures used to calculate SRB loads in order of

their occurrence from initial impact thr~ugh cavity collapse, maximum

penetration, and slapdown.

8.1 Initial Impact

Vehicle loads at initial impact were determined at three events, maximum

vehicle pitch acceleration, maximum vehicle axial acceleration, and maxi­

mum negative axial load on the nozzle. Maximum pitch acceleration was

detected by all three pitch accelerometers. By definition, the time for

this event is taken to be the time at which the pitch acceleration reaches

a maximum. Due to the elasticity of the. model structure, the time indi­

cated for the event by the three accelerometers was not always precisely

the same; under certain impact conditions, the indicated tline varied by

2 to 4 milliseconds. Therefore, the output of the accelerometer located

farthest aft, and therefore closest to that portion of the vehicle over

which the impact loads were applied, was selected as the reference for

determining. the time of maximum pitch acceleration.

8-1

The time for the maximum axial acceleration event is defined as the time

at which the axial acceleration reaches a maximum. This event was detec-

ted by the axial accelerometers. Generally, there was very little differ-

ence in the time indicated by all accelerometers. However, in those cases

where there was some appreciable difference, the accelerometer loca.ted

farthest aft was used as the reference.

At the maximum axial acceleration event the maximum positive axial and

lateral loads on the nozzle also occur. As the annulus between the nozzle

and skirt fills and the water head impacts the bulkhead, the forces on

the nozzle reverse direction and the nozzle is pulled away from the bulk-

head. This is the nozzle maximum negative axial load event and the time

of this event waS defined by peak negative axial load measured on the

nozzle strain gage balance.

Pressures on the no.zzle, skirt and bulkhead were read at the time of

these three events for all pressure scaled tests. Using the actual impact

conditions (VV, VH, 8) for each test, the resultant vehicle velocity, U,

and effective impact angle (a - (j) were calculated by:

(a - 0) = tan-1 (Va)· _()Vv

For maximum pitch and maximum axial acceleration events the measured press­

ures were nondimensionalized by the resultant dynamic pressure, q = ~PU2,

and plotted as a function of (a - 8). This resulted in a family of curves

for each locally measured pressure with VV, VH, or (jas parameters. For

8-2

the event of maximum negative nozzle load which occurs latest in time,

the effect of a was small and the nondimensional pressures correlated

primarily with (). By cross-plotting the nondimensional curves for the

pressures at the transducer locations, extrapolating, and replotting,

curves were constructed for axial locations coincident with nozzle throat

and nozzle and skirt exit planes. Figures 8-1 thru 8-4 illustrate corre-

lations of data at the three events. For any given set of full scale

impact conditions the pertinent full scale nozzle, skirt, and buikhead

pressures were then obtained directly from the normalized c~rves.

The axial and pitch accelerometers were read at the three events and used

to calculate axial, lateral, and angular accelerations at the dry. vehicle

C.G. accelerations were then divided by q and plotted VS(a - (}). The

correlated curves were used to define C.G. accelerations. The two aft

model accelerometers, located at full scale station 1826, were correlated

in the same manner and used to 'define nozzle inertial loads.

Data from the nozzle force balance was first corrected for balance inter-

actions and nozzle inertial loads then forces and moments were transferred

to the nozzle throat. These data were further adjusted to account for thei,

compliance ring and a one foot nozzle extension resulting from redefihition

of the nozzle extension separation plane. As test data was not available

this adjustment was made analytically using the following equations for

positive axial forces:

Axial Force

Lateral Force

8-3

sinn(n- 2{)e/!) . . .. . .. _ 1 t

2{)t/J[ r(l-6¢ln ). r(~ + 6¢ In) 12 ~

Where: rp

Gamma Function (See Figure 8-32)

Water density

Vo Impact velocity

Ro Nozzle exit radius

r Nozzle .mid point radius

H External free surface penetration

6i Impact angle

{) Flow directional angle

~ Radial angle

Negative axial force was calculated by:

Where:

Apext = Axial projectionof exposed external nozzle surface area

Cpwed = Pressure coefficient on equivalent wedge surface

Apint = Axial proj ection of nozzle internal surface area

The above equations using dimensions for the tested 11/1/74 and 5/1/75

baseline configurations indicate a 39% increase in nozzle loads during

the positive axial force loading and a 29% increase for the negative

axial nozzle load event. All applied nozzle forces and moments were

then increased by these percentages.

The correlated model pressure, force, and acceleration data was then

Froude scaled to full scale SRB values and used as inputs to the initial

impact pressure integration program. The program simulates theSRB

8-4

skirt/nozzle area geometry as a series of conical frustums and rings.

The skirt is modeled as two frustums and three rings, the aft closure is

modeled as one frustum and one ring, the internal nozzle is modeled as

two frustums, and the external nozzle is modeled as one conical frustum.

Four pressures act on each frustum and ring assuming a cos tP distribu-

tion circumferentially and a linear distribution axially. Atypical

frustum segment is shown below.

RL1P3 P4 t

X L.... Z

!PI PZ

RO --.iThe pressure distribution is defined by:

P = P1 + (PZ-Pl) (l-~os ifJ) +' ~ [P3+(P4-P3)

[ PI+(PZ-Pl) (l-C~S0) J !f

(I-cos 4>2 J2 -

This equation defines a (hcos4» distribution for 0 ~ i/J $, 1800 and a

linear distribution for 0 ~ X ~ L. Integrating the pressures over the

frustum surface results in loads defined by:

8-5

For external surfaces n is an odd integer and for internal surfaces n is

an even integer~

The ring segments shown below aSSume a (1 ... cos</» distribution over the

upper and lower surfaces.

~Pl

Integrating the pressures over the ring surface results in:

1T(R2 _R2 ) [ (P l - P3) + (P2 - P4) ]Fx 2 1 0

Fz = 0

1T (R 3 _ R3 ) [(P2 - P4) + (P3 - Pl ) 1~

--6 1 0

8-6

M = °z

The program calculates applied nozzle loads and total vehicle axial and

nonnal forces and the pitching moment about the C.G. The SRB mass and

pitch moment of inertia are used to calculate total vehicle axial, lateral

and angular accelerations. The calculated accelerations and nozzle applied

loads from pressure integrations were compared to the correlated accelero-

meter readings and nozzle strain gage loads. The pressures were then

tempered within an allowable r&nge of ~10% until the integrated loads

agreed with measured forces and accelerations. The pressures, vehicle

accelerations, and nozzle loads were then carpet plotted as functions of

impact conditions.

The initial loads documentation presented data for Vv = 80, 100, and 120

FPS. For each vertical velocity data was presented for VH = 0, 15, 30,

45, and 60 FPS and -9:i = -10, -5, 0, 5, and 10°. Finalization of the

SRB parachute design resulted in a nominal vertical impact velocity of

85 FPS with a maximum expected deviation of 2"5 FPS, and a new set of

water impact loads. was prepared presenting data for Vv = 80, 85, and 90

FPS. These data were derived from a direct q interpolation of the Vv = 80

and 100 FPS. The d&ta presentation consisted of vehicle C.G. accelera-

tions, 15 pressures in the nozzle/skirt annulus, applied nozzle loads,

and inertial nozzle loads.

The previously described loads were derived from test data utilizing a

model with a rigid concentric nozzle. However, the full scale n07,zle is

not rigid and will deflect up to t5° as a function of the dynamic responS0

8-7

characteristics ofthe gimbal system and the applied load transient during

impact. Therefore, nozzle loads incorporating the effect of nozzle motion

were defined on the basis that:

1. Overall vehicle dynamics are not significantly influenced by

nozzle deflections of less than 5° in either plane.

2. Nozzle applied axial load is primarily a function of total

vehicle impact velocity vector and nozzle pitch plane attitude.

Nozzle deflections in the yaw plane of less than 5° are insig­

nificant to the magnitude of this force.

3. Only the initial phase of the nozzle applied load pulse,

during nozzle filling, is significantly affected by nozzle

vectoring. That portion of the nozzle load transient due to

stagnation of the nozzle/skirt annulus flow is not affected by

deflections of the nozzle less than SO in either plane.

4. The component of nozzle lateral force in the yaw plane due

to vectoring out of the pitch plane is dependent only on vehicle

vertical impact velocity and not significantly affected by the

horizontal drift velocity component or initial impact pitch

plane attitude.

Within these assumptions, nozzle total applied load at any time (t), can

be defined as the sum of the axial force component (not significantly af­

fected by nozzle vectoring); the lateral force component in the vehicle

pitch plane (defined by the total velocity vector and nozzle pitch plane

attitude) and the lateral force component in the yaw plane (determined only

8-8

by yaw plane deflection angle and vertical velocity component). The total

force vector can then be wr~tten as,

where an and Pn are the respective angular deflections in each plane

at any given time, t; and Vv, VH, and 9i are initiai vehicle water impact

conditions.

The applied load moment about the nozzle throat centerline reference

point may also be expressed as,

Although nozzle loads vary with impact conditions, the load time history

for each component can be represented by one of two characteristic shapes.

One curve for impact conditions when VH =0 or 91 is less than br equal

to zero and one curve for impact conditions with positive values of VH

and 8i. Applied load time histories were normalized to the peak positive

and negative magnitudes of the pulse, and the traces were shift·ed slightly

to make the peaks of the axial and lateral forces time consistent for each

case. lhe inertial time histories were normalized to the magnitude of the

peak negative load.

Plots of the magnitude of the first and second applied load peaks were

prepared for axial force and lateral force and moment in the pitch plane.

+lhese data which were presented for an impact angle range of -ISo were

derived from extrapolation of tlO° data. Lateral forces and moments in

the yaw plane were taken from the slope of applied normal force and pitch-

ing moment data for VH = 0 FPS. The slope of this data is linear over

the range of tlO° and yaw plane forces were expressed as:

2Yaw force = 8.4 Vv P n

?Yawing Moment: 368 Vv-~n

where:

Vv Vertical velocity in ft/sec

Pn = Nozzle deflection angle in degrees

Nozzle response loads were calculated using a dynamic computer model of

the SRB. This math model simulated the geometry, mass, and stiffness of

the SRB aft closure, skirt, heat shield, nozzle, nozzle actuators, flex

bearing, gimbal stops and the snubber. The elasti~ity of the model com-

ponents was assumed to be linear regardless of the load range. The nor-

malized time histories of applied and inertial nozzle loads along with

peak value force and moment data as a function of impact condition were

used to calculate the time variant nozzle loads. This was an iterative

procedure beginning at T = 0 calculating the nozzle loads and applying

them to the nozzle until time Ti when the nozzle deflects to Ofi, tii.

The new values of Eli + Of i and Pi were used to reenter the peak load

data arrays and determine updated peak nozzle loads. These were multiplied

times normalized nozzle loads at time Ti+j and new nozzle deflection

angles (OCi+j, Pi+j ) were calculated.

The loads were updated until the nozzle axial load reversed • At this time

stagnation is occurring in the nozzle skirt annulus and nozzle loads are

dependent only upon initial impact conditions. The peak nozzle loads at

maximum negative nozzle axial force were multiplied times the normalized

time histories for the remainder of the impact.

Nozzle response loads were calculated for Vv· 85 FPS, va = 5, 20 and 45

FPS, Eli = -5°,0°, and +5°, and a vehicle flight path angles relative to

the nozzle E actuator of 45°,90°, 135°, 180°, and 225°. Forces and

8-10

moments along the x, y, and z axes were calculated for the flex bearing,

aft closure, flex bearing aft end ring, and nozzle snubber ring. Contact

forces were calculated for the snubber along with axial forces for the

nozzle actuators. Peak values of the forces and moments were smoothed

and carpet plotted as functions of entry condition and flight path ~ngle.

8.2 Cavity Collapse

As described in Section 5, the cavity collapse load event is a result of

a high speed entry into the water by the SRB which generates a large open

(ventilated) cavity during the entry phase•. For a pure vertical entry

(VH = 0, 9i = 0) the cavity development and collapse is axisynunetric with

the cavity wall collapsing on approximately the aft 2 diameters of the

vehicle.

For moderately non-vertical entries (a - 8 ~ 10°) the cavity collapses on

itself along a line slightly inclined to the vehicle surface and emanating

from the lee side of the vehicle base. The pressures associated with these

conditions are much higher than for a pure vertical entry but are localized

near the leeward meridian and about one vehicle diam~ter forward of the

base. For large effective entry angles (a - 8 »10°), the cavity collapses

along a line inclined at a large angle to the vehicle and significant press­

ures are experienced only on the lee side near the base of the vehicle.

Cavity collapse does not occur simul taneous1y along the vehicle for any

of the entry conditions but generally occurs within about a 10 msec. (model

scale) time span. Circumferential pressures do peak simultaneously, how­

ever, and since the critical loading is expected to be in the circumferen­

tial direction (i.e. a ring load), the peak cavity collapse pressures over

the 10 msec. time span were combined and considered a distinct event.

8-11

The pressure pulse associated with cavity collapse is approximately trian­

gular with about a 15 to 20 msec. (model scale) pulse duration. A simple

one dimensional analysis of the response of the full scale vehicle first

ring mode to this loading indicates that the equivalent static loading

corresponding to the dynamic load.is very nearly equal to the peak load

and peak pressures were therefore taken to be representative of·equivalent

static pressures. A more rigorous structural dynamic ~nalysis to cavity

collapse loading is of course recommended to establish the validity of

this simplified approach.

Analysis of the pressure. data consisted of plotting longitudinal and cir­

cumferential distributions of peak pressures at the measurement stations

on the model. At each station there were three transducers located at

the 0°, 180° and 210° meridian locations. In addition, many of the drop

conditions were repeated with the aft model section rotated 120°. Com­

bination of the data for these two drops would, with the assumption of

planar symmetry, theoretically yield data at 30° meridional increments.

It was found, however, that lack of repeatability of drop conditions for

the 120 0 rolled cases and steep pressure gradients near the collapse meri­

dian combined with off nominal roll and y9.W angles precluded a direct mea­

surement of maximum lee side pressure and distributions for each drop

condition. The approach used therefore was to select those drop condi­

tions where near nominal (zero) roll and yaw conditions were attained to

define peak pressures and distributions and then use correlations to define

other drop conditions.

Significant features of these distributions are the very high pressure

gradients near the leeward meridian and the nearly constant levels on

the windward side. The rate of fall-off of lee side pressure was found

8-12

to be proportional to the peak pressure and is attributed to the rapid

diffusion of energy with distance associated with cavity collapse lines

in close proximity to the SRB.

The circumferential pressure distribution was math-modeled as being con-

stant on the keel side (-90° ~ ep :5 90°) and varying on the lee side as

The exponent, n, was obtained from correlations of the circumferential

pressure distribution (as measured by the lee side pressure drop,

P( cP= 180°) - P( ep = 210°» with the magnitude of the lee side pressure.

A correLation parameter, I - (}cc' was found which correlated the effects

of initial horizontal velocity and pitch angle on cavity collapse press-

ures and loads. The significance of this correlation parameter is that

it is an approximate measure of the angle between the cavity collapse

line ( I from the vertical) and the vehicle centerline «(} cc from the ver­

ticCll), and thus is a measure of the proximity of the cavity collapse

line to the vehicle.

Correlations of maximum lee side pressures with ~ - 8ce are shown in fig­

ure 8-5. At low values of I - (}ec' the cavity collapses on the vehicle

axisymmetrically and maximum pressures are 9 and 11 psig for Vv = 80 and

100 fps. At moderate ~ - (}ec' on the order of 10 to 20°, the cavity2

collapses on itself near the lee side and maximum pressures rise to 18 to

22 psig. The higher maximum pressures associated with these conditions

are attributed to the concentration of the collapse energy near the lee

8-13

Olside. Most of the data for 2 - 0cc greater than 20° was only run at

ambient atmospheric pressure and not at the pressure scaled ambient press-

ure required for scaling the cavity collapse phenomena. In the absence

of pressure scaled data for these conditions, the ambient atmospheric

runs were assumed to be representative and the curves were fairedinto

this data.

The above correlation was used to determine maximum lee side pressures

for all conditions. The measured lee side pressures were then propor-

tioned to match the correlated maximum value and used with measured wind-

ward pressures to define the longitudinal distributions along the windward

and leeward meridians. Aft of the lee side wetted length, ·Lw l' equation,

was used to define the circumferential distribution. Forward of the lee

side wetted length,the pressure varied little with meridian angle and

was taken to be constant from the windward meridian to the wetted angle,

= cos- l [2(X-LW,L) J(LW, K-LW, L)

This definition of pw aSSumes that the cavity wall intersects the vehicle

along a planar surface between the windward and leeward wetted lengths,

LW K and LW L respectively., ,

Vehicle accelerations at cavity collapse were evaluated from the peak nor-

mal accelerations mea'sured by the two aft pitch accelerometers. These

readings were used to calculate angular and normal accelerations at the

dry vehicle C.G. The C.G. acceleratfuns were then plotted as a function

8-14

aof 2 Bcc and curves were faired through the data for vertical impact

velocities of 80 and 100 ft/sec. Data for Vv == 120 ft/sec was extrapola-

ted from the curves for Vv = 80 and 100 ft! sec.

The correlated pressure and acceleration data were then Froude scaled to

full scale values and i~put to a computer program for calculatio~ of cavity

collapse loads. This program considers the SRB to be a rigid body with

pressure and inertial forces concentrated at discrete points, located 20

inches on center. Only forces normal to vehicle center line are considered.

Inputs to the loads program are:

a. SRB mass dissribution as a function of vehicle station.

b. Onboard water as a function of vehicle station.

c. Lee and keel side wetted lengths.

d. Lee and keel side longitudinal pressure distributions.

e. Normal and angular accelerations at the vehicle C.G.

f. Pressure integration factors as a function of wetted lengths andlocal lee side pressure.

The program calculates the vehicle C.G. and pitch moment of inertia, and

the local pressure and inertial shear forces at each 20 inch body section.

The local shears are then integrated longitudinally to determine the net

lateral load and the centroid of application for the pressure and iner-

tial loads. The net loads are then compared and all inp~ pressures

are ratioed so that the net pressure load is equal to the net inertial

load, and the vehicle angular acceleration is adjusted so that the centroids

of the two shear diagrams match. The adjusted pressure and inertial

8-15

shears are then combined and total vehicle shear and bending moment dia­

grams are calculated.

If the pressure and inertial forces balanced with.in 3% the input data

was considered satisfactory. If the load balance was not satisfactory,

the input data was reviewed and individual pressures and/or accelerations

were adjusted, generally less than 10%, and a new set of vehicle loads

was calculated.

The output from the cavity collapse loads program are presented as plots

of lee side pressure distribution, keel side pressure distribution, press­

ure shear diagram, inertial shear diagram, total vehicle shear diagram,

and total vehicle bending moment diagram. Figure 8-7 illustrates typical

results from the loads program.

Initially cavity collaiJse loads were prepared for the impact condition

range of Vv = 80, 100, and 120 FPS, VH = 0, 15, 30, 45, and 60 FPS, and

ei = _100, -5°, OC, 5~, and 10°. After design definition of the SRB

recovery system, the loads presetitation was changed to vertical veloci­

ties of 80, 85, and 90 FPS. The 85 and 90 FPS data was derived through

q interpolations of the correlated 80 and 100 FPS data. The new data

presentation also incorporated additional horizontal velocities of 5

and 20 FPS. These were included as a result of a Monte C~rlo statis­

tical analysis that indicated that the SRB had a 90% probability of

impacting the water with an impact angle hetween :!:"5° and a horizontal

velocity between 5 and 45 FPS with the mean value being 20 FPS.

The cavity collapse loads as prepared encompassed more than 100 impact

conditions. As it would be impractical to analyze this quantity of

8-16

data from a structural design standpoint, it was decided .to reduce

the cavity collapse loads to a more simplified definition. This was

based on the fact that the primary objective was to define a set of

design capability loads with provisions to identify attrition rates

due to pertubations of loads resulting from deviations from nominal

impact conditions. The approach can then be to define a set of nominal

loads with pertubation functions which allow the loads to be applied

over the complete range of impact conditions.

The nominal loads were defined using data for Vv = 85 FPS, 05 VH ::: 45 FPS,

and -5°::: 9i ::: +5° • Over this range of impact conditions (except for

Va = 0, 9 = 0°) the wetted lengths and keel pressures are approximately

the same and the lee side pressure distributions have the same shape

with variations in magnitude. The nominal pressure distributions were

defined as the numerical average of all pressure data. The peak lee

side pressure was used with correlated data to define the impact para­

meter a/2 - 9ce and this value defined CG accelerations.

The final data presentation consisted of load plots for two data cases,

Vv = 85 FPS, Va = 0, and 9i = 0, and Vv = 85 FPS nominal cavity collapse.

Also presented were carpet plots of penetration depth and peak lee side

pressure along with procedures for defining overall vehicle pressure

and load distributions as a function of impact condition.

8.3 Maximum Penetration

Maximum penetration is attained when the farthest aft point along the

vehicle centerline reaches its maximum depth. The event can be observed

clearly in the underwater photographic records. These records were used

8-17

to measure penetration depth, pitch angle and velocity at the ti~e of

maximum penetration. Penetration depth and pitch angle were then plotted

as a function of impact conditions (Figs. 8-8 and 8~9).

The vertical velocity of the vehicle is zero at the t~e of max~um

penetration. There is some pLtch rotation, but resulta.nt velocities are

negligibly small, so dynamic pressures can be neglected. 'Iherefore,

pressures acting on the vehicle are essentially defined by local hydro-

static values alone. That is -

P = pgh

where h = distance below the liquid free surface. With vehicle attitude

(pitch angle, () ) and maximum penetration depth known asa function of

impact conditions, definition of vehicle geometry then leads directly

to the calculation of depth and corresponding hydrostatic pressure for

all points on the vehicle,. Cylinder body internal pressure was again

assumed constant, at the minimum value dictated by case temperature as

given in Fig. 8~lO, and was regarded to be independent of impact condi­

tions.

8.4 Slapdown

Vehicle slapdown is defined as the phase of rapid angular rotation and

'lateral displacement from the near vertical to the horizontal flotation

position. As this event occurs the forward portion of the vehicle is

subjected to large oblique impact or slam pressures with the water press­

~re wave propagating radially around the cylindrical surface and longi­

tudinally forward along the keel meridian. During slapdown the vehicle

C.G. is at or approximately 1 diameter below the water surface and the

body rotation is about a point near the base. The local crossflow velo­

cities on the rear half of the vehicle are low and do not produce s1gni-

-8 ..18

ficant hydrodynamic pressures. On the forward portion of the vehicle,

crossflow velocities increase and substantial pressures are encountered.

The peak pressure increases as the slapdown progresses, reaching.maximum

value when the pressure wave is approximately 2 diameters aft of the nose

and then decreases as the wave moves to the nose.

Due to the time variation of p re/isure and acceleration forces duri ng S lal'­

down there is no obvious instant when the total vehicle structural loads

are at a maximum. Therefore, in calculating slapdown loads, three or

more time points were used so that the maximum 'load condition would be

encompassed. These time points corresponded to the time of peak press­

ure at selected keel pressure transducer locations. At the selected time

points model data was evaluated for use as inputs to the loads program.

During slapdown the vehicle is subjected to low frequency pitchaccelera­

tions as shown in figures 8-11 and 8-12. These were read from the three

model accelerometers at the times of interest. The readings were then

plotted and used to calculate the normal and angular accelerations at

the dry vehicle e.G. These accelerations were then carpet plotted as a

function of water entry condition for each time point. Smooth curves were

faired through any irregularities and the data was extrapolated to cover

impact conditions of interest where test data was not available.

The time history of slapdown pressure at a given body station appears as

suddenly applied pressure decaying slowly to local hydrostatic pressure.

As shown in Figure 8-13, the peak pressure is over a very short time dura­

tion which should contribute very little to the vehicle structural res­

ponse other than some finite localized panel loads. The total vehicle

external pressure load distribution was therefore treated as being com-

8-19

prised of a low frequency base load (assumed to be static at any given

time slice) with the shorter pulse spray root pressure superimposed on

top of it. The spray root pulse load was treated as a localized single

degree of freedom system and the equivalent static pressure load for the

spray root pressure spike is approximately 1/3 of the high frequency

pulse peak. It should be stated that only the high frequency pressure

spike, over and above the low frequency load pulse was actually reduced

to an equivalent static value. All other pressures were read at a given

instant in time and assumed as static. For expediency of hand reading

data plots, the ten millisecond averaging routine was utilized as the

best approximation of the equivalent maximum static values. More recently

a complete set of differential equations have been incorporated into the

data analysis system to define exactly the equivalent static response of

a single degree of freedom system. These results agree quite well with

ten millisecond average values, based upon the full scale vehicles response

natural frequencies.

Keel pressure distributions for the forward portion of the body were

read from model test data at the selected time points during slapdown.

These data were plotted as a function of water entry condition for each

transducer location and time point. The data was then smoothed and extrapo­

lated to cover entry conditions where test data was not available. On the

rear portion where pressures are hydrostatic the values were calculated

for expediency rather than reading model data. These calculations were

based on wetted length determined from transducer data, and the model

pitch angle read from photographic data.

Radial pressure distributions were developed from correlations of previous

model test data. These data were used to define radial distribution

8-20

relationships as a function of longitudinal station normalized by keel

pressure. Definition of these distributions are presented in Figures 8-14

through 8-17.

There is a significant amount of internal water, on the order of 100,000

pounds full scale, in the vehicle during slapdown which effectively al­

ters the SRB mass characteristics. The quantity and location of the water

could not be determined from available test data so estimates were used.

It was assumed that the nozzle and skirt would be completely full and

that inside of the case the water would be approximately at the nozzle

throat with the surface parallel to the outside free water surface. Fig­

ure 8-18 shows the estimated injested water locations. In the loads pro­

gram this water is accounted for by adding it to the dry SRB mass distri­

bution.

The correlated pressure and acceleration data were then Froude scaled to

full scale values and input to a computer program for calculation of

slapdown loads. This program considers the SRB to be a rigid body with

pressure and inertial forces concentrated at discrete points located 20

inches on center. Drily forces normal to vehicle centerline are considered

in the loads program.

Inputs to the slapdown loads program are:

a. SRB mass distribution as a function of vehicle station.

b. Onboard water as a function of vehicle station.

c. Lee and keel side wetted lengths.

d. Keel side longitudinal pressure distribution.

8-21

e. Nonnal and angular accelerations at the vehicle G.G.

f. Vehic Ie pi tch ang Ie.

g. Pressure integration factors as a function of wetted length andkeel pressure.

The program calculates the vehicle C.G. and pitch' moment of inertia, and

the local pressure and inertial shear forces at each 20 inch body section.

The local shears are then integrated longitudinally to determine the net

lateral load and the centroid of application for the pressure an~ iner-

tial loads. The net loads are then compared and all input pressures are

ratioed so that the net pressure load is equal to the net inertial load,

and the vehicle angular acceleration is adjusted so that the centroids

of the two shear diagrams match. The adjusted pressure and inertial

shears are then combined and total vehicle shear and bending moment dia-

grams are calculated.

If the pressure and inertial forces balanced within 3% the input data was

considered satisfactory. If the load balance was not satisfactory, the

input data was reviewed and individual pressures and/or accelerations were

adjusted, generally less than 10%, and a new set of vehicle loads were

calculated.

The output from the slapdown loads program are presented as plots of keel

pressure distribution, applied pressure load, applied inertial load, the

total vehicle shear diagram, and the total vehicle bending moment diagram.

Figures 8-19 through 8-22 show typical results from the loads program.

The initial slapdown loads documentation was prepared for impact conditions

of Vv = 80, 100, and 120 FPS, VH = 0, 15, 30, 45, and 60 FPS, and g~ = -10°,

_5°, and 0°. Loads were presented at four time points during slapdown for

8-22

each impact condition. These data were later interpolated to provide data

for vertical velocities of 85, and 90.FPS. As previously discussed in the

Cavity Collapse section, it was not practical to structurally analyze the

large quantity of slapdown data and a set of nominal loads WaS defined

for a vertical impact velocity of 85 FPS. The pressure and accelerations

used to calculate the nominal loads were the numerical average of data for

Vv = 85 FPS, Vh = 20 and 45 FPS, and 8i = 00 and _5°.

Loads were calculated at four time points which corresponded with the ini­

tial keel wetting at vehicle stations 1009, 769, 569, and 409. Four plots

are presented for each time point, applied keel pressure, applied pressure

and inertial loads, vehicle shear and vehicle bending moment. Also presented

are carpet plots of peak keel pressure as a function of impact condition and

procedures for defining pressure and load distributions for impact conditions

of interest.

8.5 Component Loads

In addition to overall SRB loads, component level acceleration and pressure

loads were developed for selected SRB structures. The components considered

were:

1. Nose Cone frustum

2. Systems tunnel

3. E.T. Attach Ring

4. Aft separation motor

5. TVC package

6. Nozzle actuator

7. He~t Shield/Aft End Ring

8. SRM Clevis Joint Pin Retainer Band

8-23

Component acceleration loads were derived from model accelerometer data.

These data were reviewed for peak axial and pitch accelerations over the

complete range of water impact conditions. TIle data was presented as

peak axial and lateral acceleration for three vehicle zones; the fwd.

skirt, the SRM case, and the aft skirt. Gomponent acceleration loads

are shown in Figure 8-23.

Due to time, model scale, and instrumentation limitations, it was not

feasible to simulate model hardware for direct measurement of component

pressure loads. TIlerefore, these loads were generated using empirical

methods as discussed in the following paragraphs.

8.5.1 Nose Cone Frustum Loads

TIle SRB nose cone is to be recovered using the drogue chute of the main

SRB recovery system to decelerate the nose frustum prior to water impact.

The nose cone is expected to impact the sea with vertical velocities be­

tween 40 and 60 ft/sec, horizontal drift velocities from 0 to 45 ft/sec,

and pitch angles up to 20°.

Water impact loads on the SRB Nose Cone Frustum were generated using

empirically de~ived water impact pressure coefficients and a two degree

of freedom trajectory program. TIle water impact pressure coefficients

were obtained from model test pressures for the SRB nozzle and aft skirt,

nondimensionalized by the dynamic pressure, and correlated with the

local angle of attack. Internal and external pressures were correlated

independently and the results are shown in Figure 8-24.

TIle two degree of freedom trajectory program allowed the Nose Cone Frus­

tum to decelerate along its velocity~ctor but was constrained from

rotating, i.e. its pitch attitude was fixed. Water impact pressures

8-24

were computed for the wetted portion of the vehicle from the above press-

ure coefficients and the pressures integrated to obtain the applied forces

and decelerations. The wetted portion of the vehicle was taken as that

portion of the vehicle below the free water surface.

Cavitation over external surfaces was accounted for by applying zero press-

ure coefficients (pressure equals zero psig) when the keel meridian angle

of attack, £¥keel, was negative. Cavitation on the external lee side, when

the keel meridian is at a positive angle of attack, was accounted for by

applying a pressure distribution such that the pressure at and beyond the

90° meridian was zero psig. Internal cavitation was accounted for by us-

ing a pressure distribution such that the pressur~ on the internal keel

meridian was zero (psig) when the keel meridian angle of attack was posi-

tive. Figure 8-25 illustrates the pressure distributions used in the analy-

sis.

The nose cone frustum trajectory was calculated for O.2sec by which time

all forces had reached maximum values and were decaying. The results

Table 8-1. Nomenclature for the listing is presented below:

NOSE CONE FRUSTUM TRAJECTORY NOMENCLATURE

AN

AX

B

LWl, LW2, LW3

PI

P2

P3

Normal acceleration, gls

Axial acceleration, gls

Penetration depth, in.

Wetted lengths along longitudinal axis on keel, center­line, and lee meridians, inches forward of Station 395.

Pressure acting on external side of bottom ring, psig.

Pressure acting on internal keel meridian of Nose ConeFrustum, psig.

Pressure acting on external keel meridian of Nose ConeFrustum, psig.

8-25

P4

T

THDD

THETA

VH

vv

8.·5.2

Pressure acting on internal lee meridian of Nose ConeFrustum

Time from impact, seconds.

Pitch angular acceleration, radian/sec2

Pitch angle at impact, degrees

Horizontal velocity at impact, fps

Vertical velocity at impact, fps

Systems Tunnel Loads

During water impact the systems tunnel, which runS the full length of the

SRM case, will be subject to the same loads as the case. The peak normal

pressure load will occur during cavity collapse with the tunnel on the

lee side of the vehicle. The peak lateral load .should occur during slap-

down with the tunnel near but not on the keel so that a ventilated cavity

is formed on one side of the tunnel with the other side subjected to keel

slapdown pressure. Figure 8-26 illustrates the systems tunnel pressure

distributions.

8.5.3 E. T. Attach Ring Loads

The E. T. attach ring, located at SRB Station 1511, will be subjected to

cavity collapse loads followed by hydrostatic pressures through maximum

penetration, rebound, and slapdown. During cavity collapse, the ring will

be first subjected to axial pressures as the cavity collapse wave propagates

forward and then to radial pressures as the wave passes over the ring. The

axial pressures were driven from maximum valves read from lee and keel

pressure transducers located tmmediately aft of the E. T. ring during test

TMS-333. The lateral loads are assumed to be equal to cavity collapse

pressure distributions at Sta. 1511. Figure 8-27 illustrates the E. T. ring

pressure loads.

8-26

8.5.4 Aft Separation Motor Loads'

The SRB has four aft separation motors mounted on the outside of the aft

skirt approximately at the midpoint of the skirt. Each motor is approxi-

mately I foot in diameter and three feet long. During initial impact, the

motors will be in the ventilated cavity created by the skirt and will not

be subjected to pressure loads until wall slap or the onset of cavity col-

lapse.

With the motors on the keel side, they will first be subjected to either an

axial load for pure vertical entry, or an axial and lateral load for a com-

bined horizontal and vertical velocity entry. These load conditions will be

followed by a stagnation loading as the cavity collapses. If the motors are

on the lee side of the vehicle they only receive the stagnation load con-

dition.

In the absence of test data, the initial axial and lateral pressures were

calculated using a flat plate pressure coefficient of 2.0 and the vehicle

velocity at cavity collapse. Correlations of photographic and accelerometer

trajectory data show that velocities at cavity collapse are approximately

60% of initial impact velocities. The pressures Pl and P2

(Figure 8-28)

were calculated by:

VCavity Collapse

P = 2 P V~c/2

= (0.6) (Vlnitial Impact)

Pressure Pl considers only vertical velocity and Pressure P2 considers vertical

and horizontal velocities. Pressure P3 is the maximum skirt cavity collapse

pressure.

8.5.5 TVC Package Loads

Two TVC packages are located inside of the aft skirt. They consist of a

number of cylindrical and spherical shapes attached to an open rectangular

8-27

I-beam framework that is approximately 3 ft. x 4 ft. Due to the small scale

model SRB, it was not feasible to simulate this hardware in the test program.

Also, because of the complex geometry of these packages and their location

within the skirt, the flow is not amenable to rigorous analysis.

A simple analysis, however, was performed and the resulting estimates should

be adequate for providing an overall design load. Pressure PI was calcu­

lated as q and preSsure P2 WaS calculated as 2 x q. The estimated pressure

distributions and magnitudes are given in Figure 8-29. The maximum axial

load is PI as is the maximum lateral lbad which can exist in any direction

normal to the SRB centerline. The stagnation loading condition is P2 applied

uniformly around the component.

The maximum TVC package TVC package axial load occurs at the same time as

the vehicle maximum positive axial acceleration event. The maximum lateral

load can occur anytime from shortly after the vehicle maximum positive axial

acceleration event to just prior to the maximum nozzle negative axial load

event. For analysis purposes, assume that the TVC lateral load can occur

in combination with either of the aforementioned vehicle loading events.

The maximum TVC stagnation load occurs at the same time as the maximum

nozzle negative axial load event.

8.5.6 Nozzle Actuator Loads

Each SRB has two actuators located within the aft skirt. The actuator load­

ing is generated from two sources, the first being the actuator axial load

transmitted between the nozzle and skirt. This load was presented with

initial impact data. The second source of load is caused by the water im­

pacting the actuator. The actuator WaS not simulated in the test program

8-28

because of the restrictively small model size. Therefore,a simple analy-

sis was perfonned, the results of which are given in Figure 8-30. The lateral

pressure loading is P1 whereas the axial is PZ' The stagnation loading con­

dition is P3 applied uniformly around the actuator. Actuator impingement

pressures PI and Pz were calculated from the following equation:

P = Coc q sin6

cos6 = cos (8i + TAN- l Vh/Vv) cos (E +fJ)

where:

CDC = Cross Flow Drag Coefficient = 1. Z for P1 and 1.5 for Pz

6 = Flow impingement angle ~ 360 for Pl and 180 for Pz

E = Skirt cone half angle =180

tl = Incidence angle of nozzle actuator = 180

q = Dynamic pressure = ~ p vZ

Stagnation pressure P3 was calculated as Z x q.

Actuator maximum axial, maximum lateral, and maximum stagnation pressure

loads occur in the same time sequence as the corresponding TVC pressure

loads defined above.

During the initial impact dynamic sequence, the SRM nozzle is exposed to

large applied and inertial reaction loads. Resultant nozzle motion within

snubber limits then produce large actuator response loads. These loads have

been analyzed for the specific impac t conditions presented in Table 8- 2 de­

fining three possible levels of damage to the actuator system.

The actuator fluid by-pass valve will open under an approximate lZO KIP load

allowing the actuator to respond with a constant load. This value WaS used

8-Z9

as input to the nozzle system response analysis. Under some conditions load

relief provided by the fluid by-pass valve is insufficient to keep up with

the applied load, resulting in an increase in the actuator response load

to values far exceeding the 120 KIP by-pass limit.

Table 8-2 presents peak actuator response loads for the various impact con­

ditions analyzed. The three values presented for each condition are maximum

values and correspond to the three dynamic loading events of initial impact:

1) maximum nozzle positive applied load; 2) nozzle maximum negative applied

load; and, 3) nozzle inertial reSponse after decay of the nozzle external

applied pressure load.

To define the total actuator load external applied pressure loads defined

above must be combined with the actuator response loads due to nozzle mo­

tion at the respective dynamic loading events, that is, use PI and P2 for

event (1), and P3 for events (2) and (3). Use linear interpolation for

pressures at intermediate angles not analytically defined on Figure 8-30.

8.5.7 Heat Shield/Aft End Ring Loads

The heat shield concept analyzed is shown in Figure 8-31. The heat shield

is relatively lightweight flexible curtain type structure which will fail

under the water impact loading environment. Before failing, however, the

heatshield will be loaded up to its capability (approximately 10 psig)

which, in turn, will load up the aft skirt end ring. The maximum end ring

water impact pressure is an order of magnitude greater than the current

heat shield capability. Figure 8-31 illustrates the heat shield in the pre

water impact configuration. Upon water impact, the heat shield mOves up to

the position shown by the dashed line as it is being loaded up. It takes

8-30

approximately 10 m sec for the heat shield to reach this state from its pre

impact configuration. Shortly thereafter, the shield will fail as the load

increaseS to its maximum value. On the other hand, the aft skirt end ring

pressure builds up to a peak pressure of 85 to 125 psig in approximately 3

to 5 m sec. Therefore, the aft end ring can be loaded up to its maximum

value before the heat shield will fail. Hence, for strength analysis pur-

poses, the capability of the heat shield should be combined with the peak

water impact aft ring pressure.

8.5.8 SRM Clevis Joint Pin Retainer Band Loads

SRM clevis joint pin retainer band shear loads have been estimated and are

presented herein. The slapdown dynamic loading event, which occurs during

water entry, subjects the pin retainer band to the worst case of shear load-

ing. The shear loading is caused by skin friction drag. Water entry tra-

jectories obtained from model tests were combined with drag data to esti-

mate the shear loading. Using a conservative approach, the maximum shear

loading is estimated to be 0.5 psig. The reentry aerodynamic shear loadingI

is an order of magnitude less.

8-31

TABLE 8-1 NOSE CONE FRUSwM TRAJECTORY LISTING

w " 50 •• \'l1 :: 4~., ~tT" " ~.,

T e AX ,,1-1 ~DD L\.II LWi! Lw3 Pl ~ P3 P4

.001 .(/:10 3. 55~ .17':1 53.653 .':l':l':l .':l':l') .571 5~ .63,} .':l':l':l .000 46.61~

.':102 1. I'}'} 5.111 .504 74. 54'} .000 .000 1.141 5~.442 .O':lO .000 46.491

.003 1.7'l7 6.357 .'}72 96.99,} .OO':l .0O':l 1.710 5~ .157 .0'.)0 .':lOO 46.297

.004 2.3n 7.3'39 1.362 111.2')5 .':lOO .000 2.277 57; 7'l9 .O':lO .000 46.045

.005 2.9"17 8.372 1.990 130.967 .O'J'J .000 2."142 57.3"10 .000 .000 45.746

.006 3.577· ''1.113 2.413 142.476 .O'J'J .000 3.4'J4 56.900 .0'.)0 .OO'J 45.3'33

.':107 4.165 1':1.':137 3.139 lEO.534 .01)/) .1)00 3.964 56.373 .OO'J .':I':I'J 45.':I'J'J

.O'J"I 4.75Cl 10.751 3.663 175.47'l .Cl')l) .Cll)/) 4.521 55.7'l3 .Cll)/) .0'JCl 44.557

.009 5.332 11.466 4.35"1 1%.755 .0Cl') .I)/)Cl 5.074 55.17':1 .000 .001) 44.074

.010 5.910 12.\\4 4.999 ~1.096 .0')0 .'Y.JI1 5.624 54.5'J3 .O'JI) .O'J':. 43.549

.0\\ 6.4'14 12.7'J4 5.59"1 2')9.923 .O'J'J .00') 6.171 53.79"1 .':l'JO .':l'J':l 42.9"14

.0\2 7.055 \3.279 6.277 223.125 .'JI)/) .I)I)'J 6.714 53.'J57 .'JO'J .O'J'J 42.3>\5

.0\3 7.62\ \3.771 6.'11'1 230 .124 .01)/) .I)/)':l 7.253 S2.2~3 .':l'J0 .Q':l':l 41.749

.0\4 8.\>:14 14.275 7.5'3'J 242.'JIJ5 .I)I)'J .'J':l':l 7.7'l'.\ 51.4'.\2 .O'J'J .'JIJ'J 41.'J'I6

•ell 5 "1.743 14.€/'I2 7.9"16 247.3'35 .I)I)'J .1)/)1.1 ~ .32'J 5':l.652 .I)'J'J .O'J'J 40.391)

.016 9.297 15.\\6 '.\.647 257."144 .'J'J'J .orY.l "1.'.\47 49.'.\02 .'JOO .'JO'J 39.673

.0\ 7 9."147 15.445 9.'377 261.737 .'JI)/) .I)/)'J 9.371 4'.\.92~ .I)/)'J .'JI)/) 3>\.929

.01'.\ 10.392 15.>:109 9.696 27'J.696 .'JI)/) .'J'J'J 9.'.\9'J 48.'J4':l .O'J'J .'JIJIJ Y\ .161

.019 1'.1.933 16.'J65 1'J.'J64 273.164 .'31)/) .I)I)'J 1'.1.4'J5 47.135 .'JIJ'J .'J'J'J 37.365

.D2'J tl.47'J 16.36\ 10.629 2'.\'J.au .'.11)/) .I)/)'J 1'.1.915 46.221 .'JIJ'J .O'J'J 36.557

.'.121 12.1)/)2 16.551 HJ.936 2"11.7'l2 .'JI)/) .'J'J? 11.422 45.296 .'J'JO .'J'J'J 35.732

.022 \2.530 16'7'l3 }1.437 2'.\7.75'J .'JI)/) .01)/) 11.924 44.367 .'J'J'J .'J'J'J 34.9'J1

.023 13.'J53 16.912 11.&\6 '2'n.7'l'J .'3'J'J .I)I)'J 12.422 43.431 .'J'J'J .'31)/) 34.'J57

.D24 13.571 17.D>:I2 12.115 292.309 .'JI)/) .'31)/) 12.915 42.496 .'J'JIJ .'.1'J'.1 33.213

.'.125 14.D>:I5 17.157 12.31.H 291.3'.J6 .'J'.1'J .I)/)'J 13.4'.14 41.5EO .I)/)'J .O'J'J 32.362

.'J26 14.594 17.269 12.663 294.4"12 .'.1'J'J .a'.10 13."1"1"1 4'.1.629 .':l0':l .':l':l':l 31.514

.'.127 15.'.199 17.295 12."1'.14 292.57'l .':ll)/) .1)/)0 14.369 39.7'.1'J .':l'J':l .'JI)/) 30.664

.'.12>:1 15.599 17.353 13.0"13 294.491 .01)/) .I)I)'J 14."145 3'3.7'l0. .'.1'.1'.1 .'.1'J':l 29.822

.'.129 16.'.195 17.337 13.176 291.826 .'.11)/) .1)/)'.1 15.316 37.%6 .IJIJI'J .'.1'.1'J 2"1.9'.\2

.'.130 16.5>'\5 17.345 13.37'l 292.572 .'.11)/) .I)I)'J 15.7'l3 36.964 .'J':l0 .':l'J'.1 2"1.153

.'.131 17.'.172 17.2'\>:1 13.432 2'.\9.24'.1 .1)/)'.1 .00'.1 16.246 36.'.15"1 .'.1'J0 .0'.1':l 27.33':l

.032 17.554 17.244 13.556 2>:1'3.'.\57 .'.J'J':l .1)/)0 16.7'.15 35.162 .001) .':l1)0 26.52'J

.033 1~ .031 17.157 13.57'l 2':I5.':l44 .'J'J':l .I)I)'J 17.159 34.27'l .'J':l':l .0orJ 25.721

.034 1'1.5'34 17.069 13.621 2"13.653 .':l'JlJ .01)/) 17.E09 33.413 .':l0':l .'J'J'J 24.936

.035 18.973 16.961 13.626 27'l.544 .000 .0'.10 18.'J55 32.561 .':l':l0 .O'JO 24.165

.036 19.437 16.>'\15 13.534 274.672 .01)/) .'J':l0 18.497 31.727 .000 .000 23.410

.D37 19.>'\97 16.711 \3.5"15 272.97'l .O'J'J .'J'J'J 1'.\.934 30.911 .'3'J'J .000 22.673

.038 2'J.352 16.549 \3.475 267.'.\11 .O'JO .01)/) 19.3&\ 3O.IU! .052 .000 21.95'.1

.039 ~.>'\'J3 16.42'J 13 .474 265.':l72 .'J'J'J .01)/) 19.797 29 .331 .277 .000 21.245

.04D 21.25'.1 16.251 13.362 259.530 .000 .01)1) 2'J.223 2"1.5&\ .497 .000 2'J.556

.041 21.693 16.094 13.296 256.122 .000 .1)/)0 2'J.644 27."124 .710 .000 19.M6

.042 22.132 15.92'J 13.1>'\6 25'.1.615 .000 .':l00 21.062 27.097 .917 .':l0':l 19.232

.D43 22.567 15.725 13.1)14 244.739 .01)0 .0':l0 21.476 26.39'J 1.116 .000 1"1.596

.044 22.99"1 15.565 12.955 241.241 .'JOO .'JOO 21.8"16 25.7'J2 1.30"1 .O'JO 17.9"10

.045 23.425 15.366 12'7'l2 235.430 .000 .000 22.292 25.032 1.493 .000 17.379

.046 23.>'\47 15.1"17 12.671 231.493 .0'.10 .':l00 22.694 24.3"10 1.671 .000 16.797

.047 24.267 14.990 12.507 225."142 .0'.10 .000 23.093 23.746 1.843 .OO'J 16.232

.048 24.682 14.7"l0 12.301 22'J.Oll .000 .000 23.488 23.130 2.007 .oem 15.684

.049 25.093 14.€lJ3 12.195 216.10'J .O'J'J .134 23.MO 22.533 2.163 .000 15.154

.050 25.501 14.396 11.996 210.444 .000 .5&\ 24.268 21.953 2.314 .000 14.640

••:151 25.905 14.205 11."144 2'J6.237 .000 .99"1 24.652 21.399 2.457 .oem 14.143

.052 26.305 14.'.105 11.663 2'J0 .>'\3'1 .00'.1 1.424 25.033 20."143 2.595 .000 13.662

.053 26.7'J2 13.796 \\ .449 195.332 .0'.10 1.946 25.411 20.313 2.726 .O'JD \3.197

.054 21.096 13.612 11. 305 191.2EO .000 2.265 25.7'l5 19.799 2.949 .OQQ 12.74"1

11111111

8-32

TABLE 8-2 SRi'! t\liZL.:LE ACnJATCJR RES PONSE LOADS

• •

(X}I

Wv.>

ll1PACT CO:\DITION AC111ATOR E x 10- 3 LBS. :\CHHTOR F x 10- 3 LBS.

fh ¢ NOZZLE AXIAL LOADING EVENT NOZZLE AXIAL LOADING EVENT"VH I'L\.\. POSlHAX. :\EG. REBOU~W ~L\X_._ POSjHAX. NEG i REBOUND-- - - - ~

- - - -~

5 -5 145 - 60 - 120 +120 - 120 +120 - 70

20 I I - 120 + 120 - 80 -120 - 120 +120

45 - 170 -120 +120 -210 -120 +120

5 0 + 40 - 120 + 120 + 50 -120 + 120

20 - 50 -120 + 120 - 50 -120 +120

45 if -120 -120 + 120 -120 -120 +120

5 +5 + 60 -130 +130 + 60 -120 +140

20 + 40 +120 -120 - 90 +120 + 120

45 -120 +120 -120 -120 +120 -120

0* -5 +90 + 80 -120 + 120 - 60 -120 +140

5 +60 -120 + 120 -120 -120 +140,

20 -120 +120 - 70 - -120 -120 +140-~--

35 + 50 -130 +110 -195 +160 - 80--

45 ir - 90 -110 - 60 '-320 -380 +200

0* 0 +100 -120 +120 +100 -120 + 120

5 -120 +120 - 60 -120 + 120 - 80

20 I -120 + 120 - 60 -120 -120 + 120

45 r -110 +120 - 60 -210 -120 +- 135

TABLE 8-2 SRN 1\0ZZLE I\C111ATOR RESPONSE LOADS (Continued)

ex>I

W.po-

D1PACT C01\:,l TION AC111ATORE x 10- 3 LBS. I\CTUATOR F x 10- 3 LBS.

NOZZLE AXIAL LOADING EVENT NOZZLE AXIAL LOADING EVENT "'1I (h ¢> NAX. POS . NAX. NEG1REBOUNDUAX. _~O~. }1fI.~. NEG LREBOUND

- 120 ~ +12~ r-- + 70-

5 +5 +90 - 45 -120 +120--- _0 ___ •

20 -60 -120 +140 -30 +120 -120

45 - 70 .,.120 +120 -120 +160 -130- - -- --- -- - -

5 -5 + 135 +120 +120 -120 - 80 -120 +120-

20 +120 + 60 -120 -120 -120 +120 I

45 +225 + 120 -120 -225 -120 +120

5 0 +110 -120 . +120 + .io -120 +120

20 +120 -120 +120 - 80 -120 +120

45 +150 +120 -120 -150 -120 +120

5 +5 - SO -120 +120 + 70 -125 +120

20 + 60 -204 + 120 - 20 -+ 120 -120-

30 +120 -270 +120 - 90 +110 -120

45 +120 -270 +120 -120 +120 -120

5 -5 +180 +120 -110 -120 +80 -120 +120

20 +140 -130 - 50 + 60 -120 +120

25 +210 -120 - 60 + 60 -120 +120

45 I +370 +530 -180 - 20 +120 -120.

5 0 +120 -120 +120 +80 -120 +120

•

TABLE 8-2 SRM NOZZLE ACTUATOR RESPONSE LOADS (Continued)

•

C»I

WVt

DiPACT CONDITION ACTUATOR E x 10- 3 LBS. ACTUATOR F x 10- 3 LBS.

Oi ¢> NOZZLE AXIAL LOADING EVENT NOZZLE AXIAL LOADING EVENT :VII NAX. POS MAX. NEG· REBOUND HAX. POS NAX. NEG. REBOUND

~

20 a +180 +120 -100 -120 + 70 -120 +120

45 +270 + 180 -120 +30 -120 +120

5 +5 .- 15 -125 + 120 -70 -120 +120- -

20 + 90 -225 +120 + 25 -120 +120

40 . - 30 -285 +120 + 30 -120 +120

45 ~ +120 -255 +120 +20 .; 90 +110

5 -5 +225 + 115 -115 -100 + 120.

-120 + 115

20 + 120 -120 - 70 + 120 -120 - 50

30 +120 -120 - 50 +120 -120 .,. 60

45 +225 + 129 -120 +230 +120 -120

5 0 +110 -120 +120 +120 '-120 +120

20 +120 -110 - 90 + 120 -120 -120

45 +150 +120 -120 +150 +'1'20 -120. .

5 +5 + 20 -120 +120 - 80 -120 +120..20 + 60 -160 +120 + 60 -140 +120

45 +110 -160 +120 +110 -160 +120-.

* VALUES FOR VH = 0 MAY BE USED FOR ALL¢ ANGLES.NOTE: PLUS INDICATES ACTUATOR COMPRESSIGN

MI~~S INDICATES ACTUATOR TENSION

i.• j-- ..,

." 1'-

I .-

-rII

,! -.-

!

II

--J--- .-i---I

jI._---- i--

I!,

, I.--" -1-- --"i- ..

ii

- . _._._~--_ .

"1

---~-----­

I!

20 I 30 ; 40 I(at--B): .. --i---- - -1-----1--I . i I I---j----+ ._-;,-~-----~i

-f-:--­II

10-.1

I

-~------ I

II

.- ! ---I.

i--·--f- -

iI

i

I: I

--+---~Q

III

,II_._-1 _,1

, i ,. 1 .. 1 . I '

19 ; 20. I 30.. I 40 . I . 50.---i-----; -- .(<x-d-E-J--j -~-J---+-_:-;-J-:--j---j---- .L_

__l_~ .J_. I_.l LJ L__CORRELATION OF INTERNAL SKIRT PRESSURES,: ,--MAXIMUM PITCH ACCELERATION EVENT i I

. __.~. .... __." ... _ .. ,__~._,.. _-------..<--. ._ ...I.... •• _.__ J.._ ., __ . __ L .. _

o

;._-_._.

o

. 008

1---­j

I

.020--

I"1---

I,,.016

I

.. 1---- ..-. _--' .I.. I

I.012

!I·

i

i.008

ii

-.-1-Ii

-_--I-

I

I___J __

---TI

---i_

I_.1.

----r .004­Ii

--rL._.~ !-. _

II

......1._I

._--~-!

J-----

~-~- i·-------+

!-----++I

D37/q -i--

I--·--1--

I---I.J \

I-­II1--

I

D26/q -~ .004 :iI

._.._ .._1 __

I

I.- --1-- 0 ~---- 0

-~""-_.. .--- ."----

_L ----L 'I i FIGURE 8-1-

.1_ _.~_____ __ ... _

--r-I!. j--i

-j--I,

+

i'----

,'..

8-36

.. 1iI,,

- --II

---Of .-,

.. \

I

---l .Jj-'" 1- -- I

I I

.1- -

-tof

---l-- --­I

. I+__-_L._

:.!i----- +--. II I

-~--7+---I' II It:- --'--j- -!! . i;.c-r--fI, : iI: ,

j .. -

-~-J'

!L

; .I

________ J

iI

.._.~ --I

!.- t - ..•-

40 50-----~--' -!-------~_.

, ,i I

I I Ii I--+ -1'-I I

. iI I___ i +__I . .i i. i

--~------- TII----1"

I

20 30 .

I(a -- -8-}~---I I

! __J

10 I, II I- :---------1----i i

I

-- -~-·---r--, ,ii

-----1------- -

---f - L --I,I

I I

o 10 i 20 . 30 40 I 5p___ ~--- ~_ <-a """t8..).-I-____ __J ~------;--.I' .' I' i II! ! I . I I . i..... ..... . .. L_(-_·r-t ~-·I

-----'-------J----- ,----J------ ---J:--- -··~~--~--I---FIGURE 8-2. CORRELATION OF BULKHEAD PRESSURES,

MAXIMUM AXIAL ACCELERATION EVENT

0-

,---i--

I,

t._.---L-..-_

-----t---I

I------T-

II.03,Ij- <i>

.02 ---1--,I

,

D32/qI

-j- L

I,i

.01

1--- ________.''_.1 [----, i

"

If----.. _----!-

,!I

Li

I II I

r- .03I

1--- - -~--I !i---

,.02

! ID31/q ----r- iIiI.- --- .01I

i I

! !i--- r---- '--1-'-IIr-- 0

! 0! iI I

IJ._..... --- -T- ~---~_....- .

II

-1'"i-.. j

i

r-- -~

8-37

8-38

-,

- • ......, ,"_ - "0-

1

I

-II

I--1-'-- --r-'

--tI,

__ , .____ i. l----··

I

I

I.- r-I

i I1 _ ...._--t­I

IIII ,r----r---·I' ;")----1 -.i

,1

..... '-" ..!"-

····_~--·--··--·-·-r-·-·· T'I I Ij I ', I I

_·_.JI~_ t---~+-i

----j ----- .. 1-----.1---

, I

jl----1---, . I

i I I,.-----j--- t~'--'j-'-'

!--~, ... - -l~.+-~.---:I I I

------1._-- _...._....l._... ~-~... ;_.n!)-...:.'o.......t:l,.! I

i-----! --_.. ;..­

II

I___ . .1 .__ ..

J

---T'---!

..,..··-t ._,,--

iI

TEST TMS-333

20 30 !, (at":" () )~. ., I ,

1-_.+-

I

1i

I'; 0

;10

!-.- -

r

.001

Io

~_~_t_"'--+-r_'-_8_§_J_iQ---i-e-..,..--.-......-..,,_.--~

i'

o 10 20 30(a- eo)

40 50I!

50

- .001

oo 10 20 30

(ex ""0+1--: 40

-. i

,.... 1-··---·_·_·· ,. ,

I

I. -,_.----_.

!. --. --+-~.

Ir 1 ._._-..;...•_-_ .• - I ..

FIGURE 8-4. CORRELATION OF C.G. ACCELERATIONS,MAXnruM AXIAL ACCELERATION EVENT

• __ 1 .••. _.__ ,.__ ,'. .• -1.. ..••. __ .~_J_

8-39

I) ')1 \ _--I....l.J...L.~__~._~)"., r r ;-f' 1, __:_.:.....:.1_'· ',IT ,') 'I T ;~.:...[ ; tjl'rl·'rr" :.:..LLl..:....LL.1...Li

8-40

I-fi

, I

.;

-: ,~-: 1 .J :' I·r·····-.··-·;·~ .•

i,,)

l''r"!

".j

I

,.,L

!I,

.f·"1:

/'

TEST TMS-333

"'1

::1;1

-toI

,I"I

IL'

! 'i'" :;

j,

,,I".

I

: : 1

I ,Ii--~' _._-,.-:.,i

·l·1

'1

,_ .; i

:

I '

l';··

i,

i, .. ,,..-r-"~ .

"

I

TI

-;

.i­I

.)

-":-r~'-'I .

•. J: ....1 ,/:.:';' , __-l......

FIGURE 8-6. CORRELATION OF C.G. ACCELERATIONS AT CAVITY COLLAPSE

8-41

1

2

4

3:

5:

6

. 0 "(llIo-----<---1-O-----'---2-0---l""I~I"!"'3-0---........;.---------:-.....-i-:::I""""""--:--.;.,........--,.--

(<\i'-~~'}

-5

-2 .

-4

-3

I,

!.

FIGURE 8-7

NOMINAL SRB WATER IMPACT CAVITY CGLLAPSE LOADS-~ -..----_. .__ 5/1/75 FULL SCAL~_..cCJNFIGURATION _iMPACT CONDITIONS VV = 85 0 ~ VH -:! 60 -10 ~ TH ~ 10

PHI = 0 AND 180 DEG PRESSURE DISTRIBUTIONS

........

V ~/

/\

,.....(!).... 200.Uln.~

w 00::;)UlUlW0:0..

"00. 600. BOO. 1000. 1200. •"00. 1600. IBOO •

Ulo<o...J -20000.

z.......en...J

~ -10000.

,.....o ~

,-

I1\ \ 1/

\ \ lJ\ I

" -VItJ

."00. 600. 800. lOaD. 1200. 1'100. 1600. 1800.

1.00XIO+06

Ulen...J

o~

0:<WIUl_I.00XIO+06

v .... 1"-.V

i l-..... \I V

'- L./

-

I I"00. 600. 800. 1000. 1200. 1..00. 1600. IBOO.

/ ..........r-- I--. /---I-- - I-- ./

Ul •. 00XIO+07

en...J

*l-lL.

~ 0WLoL

(!)

Z -1.OOXI0+07....ozwen 'tOO. 600. BOO. lOaD. 1200. 1"00.

VEHICLE STATIGN - INCHES

$-42

1600. 1800.

I1

::f6"Mtiz

Ilf !llrlll!I!III,IIII,I,! 'iW~~!I!!lllllql!:,' ~Wnll!II~ljlil Wl~!l rrrtJ.111ijl)'1 j TIJlj11!;~f!tl.!W!i!!I.j:, '1m, ffijll llWilf1.'!I!J iii! iii! Iffllf,i.!;'IHUril',llt,14! ~:II th~} 1"~~tf+I'+tt+Jtj-L rr' () 11~'I!w'ttl~'t{It+d'" nr'i+'~I"J''''r;.Ij.;II[' tIl,tlif! J1 i I Jill! Ii'l I I: 11/1 II II :1\,1 :11' ~~. I(~~L l,I r II 'j jill TIlil ill!! r! :i!L1[t:i im :1:·: I,m !.'ii!'I',1 1F: ;1 '

I II I I ' 1111'1'1' I'" <III 'II .. "",,!.. I 11" Itlll't~I:;llt .. I.'''I,tl''I'·il'''1 1 II ' I I 'I : :' :.:" .:.:.. .' 'i, II.,,! r: ~ i 'I:'" I' \ 1i 1.1.1 !Ii! j i.!; :1 i : II i:. III

I'i' :' '1' en i~ll~i'r, t ~:I~~II ";+t', t1f'Hi.~h:~jl·tltrrr.,'I+I'+I:I:H+t~i 111 \illlllllillillliillillli ~)~ ." ] 'j ::' '~l It . I l' j' Ii '.~! i i : l:1~j,i, !'I'1

11iI ! j

1m :/1 Ii N; I ill I II Ii~IH+H+H+ttt+HI II ~ ~:1 i II i l; IJI , I II .11: I 11t;· tttt1t,+H,!H.ttttH

1\\\1111\11 . II Ii· i-ij,· l ,(!j I t I • I' it 1 !'~ I ldt l' '1 tJ irI. . jJ . jl II ~,.I: .. I I It;., :,ll! :..l< Ii '1 ' ~ I . ' :1 IUJ I, , ~l'·. l~[l:IIT

' I I' II j II I IT ~t \ fjJ ,1 I) 111 II I 'I' ,., I I ~ "I itl 'I ..~ ""r:ii~

Ii III I It I Ij'l I ·I! ::1,' II ifJ1

, I lif'iI !./';I' I~ u.i! i{{U' ~(1 Iill i I III :i'I' i :1111 UI i~ I Iii; :i,: :!1: !i!: !i:! I!:: : jII, ,I I ' I '. :.' I :I'!I !I/.:~:I I : I I' Ii· I::: II' I II I,I[i !1!llli: I:!: I::: i:i! I,'," ij[i'

, , ' ''' I I I I 'i.. ': i , ",II· I I , III ,I , 1111 """, I." ... 1 . ,,' I"

IIi 1'1 j I I i .jl, II, III lilli' i~l! I~: !I\!~ I 1'11/1, PI Ii I!!i!!i' 'II 111 II!! I!!I i;iT !II: :q: :!I, li'! :;:1

I! ,1]1.1 II .,~ I~~ li1 '~f 1 I 'I' iI 'lfljt! l! !"! li~ Iii i ti!Hiii lii;jlji :i~t 1! I I t I j lttL~ I lit! I lilt! d~ ,inl !~illjl1til I! 11m TI' jir '!llllil 'flj ,n~+I-r"++,,lttH-tll:: 1 I t I I., ,: ,fi1~ti fir. H+ ~I';~; !iii,

ltHtt!1f#ij+H,-ttt:-ttt,:+11+' I, Ii I ,'I 1: I /I, I ~ I',., I 'lift :11:~ I W~WiITmff:tt~~8t~L,ll il!l~j (11+1 ~t.. 11lr1 !II. II! r,~t ! : !~ iii!, ,'II' lift Ii!Ji~ mil! ,l1i!lrr!1 !:~! ~:~,~ ~ lW~1Il lI h rl :H11 Jill I II!! I II!I tIl 'I ~J..II· ~.:I 11,1 I r* 1 11" IIIIII. ,ll\'! ,.,,!l.l. ,.,. ,ILl "I\tIT~f

j'l' " , r 't I' . I I'm.~: I .~' "H" I J'I II I' I:., 't ",. ", '" A[If! ~11 +rli ! 1 ll tj til II i ;lil I: r ': ~tl HJ~ ~. rJ 1T': J ;~ jT I ,111Ii:! ilil ;:~; :.:~ rh: ·;~i :,, " 1\ !, :ill 11\ I ,\ ill\ I . : 'iN- 0, ;#0, • I, II, \' lill 11\1 'Ii 'li, il•• iill ,:', ,ij: S I':: ,iIz' !i I! ,,' lUI ! IJ.' i~ IHI ~l 'I.~ IllIlH H0: I I L1' ~~j +i'l l'i:'~I' . 1+1 '. P ,'.1 ;..! ltlt ~ H~, '.:~: , ~ ;u .' ,I, I,'! ' ' I ' II ,1 I,; J1 Ii! i; Ii III ~ ~w

1 ~ I, . o"~'; j}:; \ \ 111\ III !'[lll'l j \, \full:;: .,: ~ >'I

f

'' ~p. II"~ :~jl.~ "it~ ~;l Ii lilHfi IAAIIl+l'H~~;:H,q~Zi.t·!l: 0: I ,.,1 , 1"; III ,1. il· I III' Iii Iii; il! 1,·1 ,." 'II ILl I '

: ~I Ijlj,l . i jll 1~11: 'iJ ' :J liJ:H~'I' ';'~,I'! I' I T: I. I. ~1·~~,'I~n! i' /It~ im !mIf/'Lifft ' ~Il. I!'!~ [' II ':>', ,fi! IV.I!, ~jm1Ul . i r' I 1 1101 'f 1 ][,. ItI' ,1-1 .1 .IJJ 11f·. ~ i :> ;'\\ 'j" I I!TKJ!, 1\\ "11\ "r) :11:): ,;1; II Iii' :; I') Iii' I:'! ::. '" I: I i

"-'H+4+H+l+ ':""" 6>:'~:! , .. !'!'.tIH~I~ J+:.!.j"IIW4f4. H :.1+11.-:t! I I ' " rm ~ I~!I,~ I ;1 , Ij I:,' III: '1 I I Ii I : ! mr :l!i ,; Ix ,: !. ,S f II ,Iii ll!i r.f; :~ j '1 I" jL il rill iliiill '~ jll! l

-; I "I I Itill ,j. 00 rtitf'~ ~'I I, r I ' ,~ r I rr Ii~ i rHi d,1 ~

'IIII I ' I I' I [, I . ! II 'I' !!,! I!i r.<:l i! j I"II I ' . i I. ~ trti 1 ] ~ I'Hj'li::'lii g:\tj 1 I It .. ' Ij :i!1 ! l i I 'ItJ1 !!!, ill ~ irjl 1 1II I i 1 1 l'i iii ii itT j'I1': i 1

, ' I "i l\dll\" i:~ ~~.~

I ! j!. ,·1 + I J I 111./ /J ~ j fij'! i, ,ll'llllj::, l~'lil,d! jJ;.:,[~ !jrj! \~

IfU I ,I I I H11+ 1111 t, [:; ~ I I

:ltllttti,itti ~ 1[; lJr ' i f '1!lif!1 I It, ~1~rUi~ .!il®I r ~ II 'ill I ~ I!. . .. /j~ ,'j j f ~I! Ii II! II 11 IW),IH+H-HHI++1+H+H IW I "" I " 111 \ 1111\ \ II

1$tttttHfttfttt'tttttHh·. I 111. 111 IIII II Ill!

I I' j 1~ w ~I t!1f+·jf11+ft+I+H

.111. I j; _J, 11,1, ,I ,!,I JL /lliltl!l!i111jji!!!j!J' t

l1 II ~JiMII;HI (4) H.Ld3a NOI.LV1l.L3N3d 1;ln~1t ',ijd I 'In jtl;l) Ij i);lIlf1 Wi I

II Hit 1111111111111111111111 HIllflllnlilll 1 ill IJlIIIII i lliulli l-U.L1!111u..u1iI...............8-43

.,

.' <M

:lr,,.,.,<'M,"",,no

r·iii~l;~m~'1'In~I"I'!I;~II'~:;1;~n~i: ' :riilji !i,i[,!,f i/'I!lliiif: ,;!:I 1i!II': ;'!lTfiilBf1TIf!J!!; ! 'I'! .i:~ .. i,lif!: i[P:!i;1fj0?ir:':"i'lT!r~1, ,,, 1'1'1,1 " .. I "I ", 1'1 , .. , '1l1l1' , .".11. \" •.•1::: I .. , ",' [!!;1iI1, ... "., l' 'I "'II"" . 'I' , 'PI rl 1'1 "" ,'11' 'I

' I' \ : I :', I • I I 1 I I" I : ' I j! I • I: J:' I I' :" ! ~ Ii: I " I, I l (,:, . I , ' , . , . I 1, ' " '" I,' . ':' : :!.' :,1 11/1/74 CONFIGURATION !I '1\:" I II!! ',' I:': l: ',.: :1' III ,.,\ \I:l:l 1.1', ,

" ,. J., .,. I ···f :r:'l' .,. '''1 "J r'~'r' ··nT·'r! ''<1':1'" li-:jl r1 •1 "llll! 11' '1' I""'"' ,',': , " 1 'li"""'II: ,,: "1', "I" III :1.,'11 11 "I 1111';1 ',1: " I 11"1 '1IIfl" '11' 1'11" 'l";"~' I '1'1' :," ,', 'II ",: ' ,,". "1'1'"' • II' I '1' I ! I, 'I' II I I' i It \' I' \ \1 I" t '\'\\' I ' \ \11 1 , ,I 1'1' . '\

" :. .'. ,:;I' !, I,' I" I'!:; Ihi: i' I' .. i II i!!' I,' . I: I :[' !! Ii, i1'1.: I j ;lj'I ,';' '1'1' '!I, .:- I :'F :It· 1'1 i1:, ::. ~ ! Ii' I : : ~' I, ,;II: f!', " ,.;'I '" I' ., 'I " '", "" ", W' .. '/'1 II, I I' 'III .,' ,I 'II ' , I I '~l . ,. 1 ·1 It I " .1.,11 \ . ""I" ,I I" "I "" I' I· [I I ., li'l'l I : I. ' II: 1. 1'1 I II: j' • 'I :.' 1.1 1\' 1 1,;\ ,I ~', t~l·'I.\ I •• \1:," ",' .\,:;' I II" ,. t';I;'" ,.. '1" 1,.1 •• r If" ~.. • .l.d'm H" ".' jJ . .;M -" •• ,L· •1 I~' •.1.,. '-n I ,J "1' r-l .-.-l'·'ll.;.l ••..( r'" " .•.. ,.

, ,', , " "'j I "'''l "'1'1" I' 1:11" I'" " , . 'I . 1'1 '., ,I \. I' 'p"'" 'I" I ' .1'1"1" 'I "',' ',; I" '\., I \' 'II I' i'l "I', III " 1" I ': 'I I' 1\1 ,; '1 111 ,'\1. I." i " \; , '~I Ii I' ",I 'II:, :" '\ h 1'1' i' \i I':' I \ I ·· ..1,\" [" '\. ,

,,·'1'1' :'.. 1'1" I, (, It' .. ,I III :r' J ~;l 11,1,' I I:' ill I." L ~t 1: 11 'I U ,': lI'l ':1.: .• !: ""11 '11 'It tt':·: 1'/:: ! .:,: . I :" '1"" " ,·f .! ::: Iii. ,':: I( !li!rl!.ll ,'II/Ii::, :., ,i!l lli :jl:: 'I!i .'ii ill;' !:i; : l':!i~:' '!'J< ,iii I': 1:1::I,~:: Il' Ii::, I',:. ::11 \,:1

, .,,' ";, , :,' :--, h:1 :;~:I-tf .;.j. : .. "r,ttt: "'f '~I' ~I!' '~' ~!tt 111 "'Ihr'~! '1;'-; .. ".l:-~ IJ;j1~':' ,~~'~~I:' ~: •. , .. j -I.:" ':I:I":~, ',' ." I I' 'I I" I' I'" li"l·I '1 'I!': "1 1[·1' II' ,,' UI . I"ll" ',," I ~ .i l ·l "" .. ''\.\ '\" "I( , .,' .. , 'I',", 'I" I' Iii! .. j • ~ :: I 1,1:1 '1 , ,1.1

1

I I 11 id'l ,~: I, ~l :, ~'J 1,; ,:,\,,'11 1. l'f l ,:t'l j : 1;11·': l~ I: III, "I 1'1,:':,1 I

: . I·.' ''': ,': "I II' "., "': II'~ ,'d If'' ,I:", .. :.! ,.J 11 ,. ':,t' I"~ :1' II. 'If' ,·.ll··,l :1·\ ,!:- .rl' "1'::" :' ",' 'I:' ''1', ,. "ill'''!! ' , ",. " , " " .. 1 ,II, ,"'. '1 1,. j I ,. I" '111• I ," , I, 1I' "I ,I 11" ,I. . ., 'j" p, '1'" , I'" ""'1 11\,"i",' 11 '\ I : ,I, ' 11"1 :",\'. JIlt,,: i \:' i II (~:: ,111, '1 til'l\ ,I I,ll,:': ,'j' ',,', " • I:. • "1. '~' I' 1'1 ,I:'

"'j'; ." ,,"I' 16 i 'Ti:-I" ""1' Ii :"_1',"1 ''''1 Ii' ;~'l "I::I--,'~'TT; rllill~-' '1~~'i~iJ t'::\-:-, :··1·· ..:· :;.;Ii;-;\·:'·'I"·I· '1';: 'j · ..·1·" . if'::',J. \ 'II!" !I': il :. !::l ~~l" :i' II: f: '1:,1J!. :I!~ :'I!:d: I!;; !i:\ ,:, ~'~:I:1 ~ 1:l::' :P~:, ::::I':l i,' 1 ;;, ;\,i/:l, : I'" ; ,;,1''I' ,"., 1'1 " I,. "'Irl ,·!lnl·) 1'/'" ., ,I,·" " .!.\I II" 1\.1 ,!~I 'tJ .1.111" ,11'l'll' '11"'" h, I.. ·, I' I I ,..."., ,I,· I''~ '. I', ,J,::. " Iii! ,:: ,\,1 1 'I"'i" ::1" !'j!;' ,',II; ',i l.: (1)' Ill! : 'II \I'I! l'l' 1,\\ :!'I i:;i ',i:l i.'III~il' ":,:'; ":':': ',i I, : I .liI':,

J t I' 'I' t" I" I ',. I 'I l" "I'l .,~ tt' I 11 ""/'" ,,' II, I. " I '/ ",II, I " , " , ,I '.,· • l' ,'•• , ••.•• ··'[--r· ." , '1~ , t· 't···· , j'T •••.•0- "'1 - ., .. , ""\' 1· .. >I"

I,:'. '" I' ,, :,' I. , ,'I', " , ',1:""'" " ' ,:: I' '1'1 ,Ill 11'\ I ,', tl' I'll: I 'I ,II:: ' t", ","',! I" \, , , . .. ., ,I:: "

I '1'1 I" '1'1 ", ' " "1'[/ '1,' iI'I.I, '1 1•1

1' , '11 I I", I I{ \., I ,1 1'1 "l{ 1.1·" "1"""1 I' I.. I II.I I' I·:'· "", " 't""'" 'I'· "\': i I' il'il:'!' 1'1,' II!: :,1 1:1 I.:tll,j t/\j-i'l "ltqi!' t";pll: Iii, .,': ::: . ,,'~, I';

',. ,', ,,:: :;:1 ;:"', "I'" 'I"~ "t'\ :I'l~ ,J.U· 1'11;1 til;j!ltl'l,:'r: :!:. :1 I,: I'i' 1"'~'t'lll1"I"lii lilll'II!; i.:.i ,; .' I' ',i

I I1

1' . 15 I 'III' , • II., '';11 , I l' 'I' I I" ,I, I,." t' ., i, ' II 'l 1~" I '1" " 'l.! ,. I'" t" I ,· ,,,. "It . '''1'' -, ..,,, t···~· t-t· ..; '7T" ~" .... ~... ~ .... ·t· .-.... _. -_. '1'" '" ,.•-. '" 1'1' .. . ,....."1';' II 1'1" " 'l' "~I: 1',:\ 1 ' 'I 'III "I ;\:, i'llllI'I' ,jli'AuuIENT :PDC'SSURE '(14"7 lpSIAqlill 1 "Iii I'i :'," :1' .

, ,.: :: I' ' : I I' ';i ' .;... ',r .::: '!:: : L i!l t1 L " . t, '~' ..\l·W : ~u;. " • I. , '.::..l: '! \1. i I: I. !:: I' I' I' I ~ I:

, ' . I ',':!I: ,':,. ,I-.,~ ", ll,' '1;'--,.:1 " "1'" ""I:I~--:-"-',,:' ':~I:-'·' ;--~'-I':i;TII-I""I" i;: ':!:iI: l! I, I .:· ,'II ' 'II. "11'1. 1 , ,I, I "4" ill; II ,j I l1 j' ' ,II 'J1+I ,I .. , 1" •• " .. "i-1 . ·,,·1 .. , L'j"ll " i'· . ":' . iil~ "'1 :I( :I:i i'I!; iT1Uii~ tnl'lii1\' .trfj:ll'j TJT1~, 11[1 I, '11[; ,TIl l1r;imj"l,r'll~nli';: ill! ~:: iTlitl'"': :!;:I':jT1 ii(l'i:', T:i~i':I';i :'-:'

I, I 1"', I I III I I" 'III'" It I 'I'" I .r 'I " '1'" I' ,j I \111 I I' \' I, l' Ill' ,II ,., j'I" I I,. I' ,"'" . ,\. "" ". "', . \1 ,. II" r'I"[ \., 1"'1 1'''''11' , 't·· .. " '1111 '1"I"w ",,' ' .... '.,. J', ", I ~: ' ':1 il:, il !ll!i l:,: Ill! :rii if:1 ,!i: :'('llli' llli' {:~ llit: :~!: i,'·~;:I,'.·:: '::1;: i:~:!A :Ii,,;i!; !!il::: ,:'ij,;" :I! ,'.',.. . .... , 14' -1'iI11' ·'·.... ·1 't

J r~r 1.1, .••. "1"'1 ~_.\' .,d .. w1'1> 'T" '·1·l.1t ..• '····1 ..... ·<.; ••w •• r..

I..··

1--1 I I-I. , .. \....· . "I 'I ,I, II . I .,~ I II' I 11'1'1 "I 1"1' "1 \11'/ I' I I I' 'I 't 'I" j' "'j" I' "f' I ,.. , . .,r, , " ,,'; ,', ! II ii, ,. i Ij I' I::;! I' II:: I I.: I, :I! I,' I' 'I: I' I ::11 il' i" I: 1,[, [11):, 1,)1 I :ill i! i'll' li:: ,l!i II,; ': I .. ' ::!' I::: I:: ,; i' i", , : 'I' :' ITII'!' , \,h! 1,,\ jl ;"!Il:[, :fJ!H"I,i. 1j' .I;:I,!'I\ 'lh ~!l ·If ,'::I;f:' r' ." , t I'. \'!r' 1.,\ 'I, I: . I,:,! '''.',11..

, , , jl I 11I 'j ,1'.' II' " I., 1 '1, .. ,·11. ", III III' ~" I I '11'~'I~' I·, " " 'I '1'1,1, II,d .I, .. '" . ..' 'I I '' ,'II " II: I.' , lIt I" I' : ,~I '1 .~ i ,L I I, 1\ :, j;,,, I : I I,';; l'" I ,I: I' q I : 11'1' I; I !,. ti: I I I' \I' ~ \ I.· ~ .. " .. Jr····· .... \, .. ,.h·· + ,...... , r'" .In "\", ·t' '+r ~ .... --'1-' ,"~·tl.," ... !, _ ..... "·-1·'" r" .•" . , .•.. ,, , -::?: 'II:!,I I:, T, ,'::-I"i,1 !1:il:lll: '1 1/"':11' 'II Ii, !:j'll III"" t':I':,I",' i:li1ii"1 ,:1; .ii: i.'\'II,:, ,!'il.·I;: "[I .1: ,;'., \ .. : I,,:I ' "I ", 'II' I 'I' '1'1' II ii' I .. I') ,.. , 1'1' ," . II' It'" 'I' ", IIH· , "j""'" ,.',.• 'jl'I' t-,> 1· \.. , t'l' ,.l-j'" 1t"'I'" " "11 '. '1" , •. , .. I " .'. '" . ',.1(/):' , " " , ,I'" I 'i 1\' iI' :. I" I 1'1' I I I',: '11'1 I .1,:, ' . i', Ii "I' l ;I ; i '" I '. : . ' i'!" I'·:'· ,'. '\'

, ,... . I t l 'I I,' :: ' • ; I ; I I l I: I. I 1, It,. I . {i ~ :ii, I I : " • I I I " .. : , \1 ,I I I '. I 1 I· ., : : I I I:' I· . , 13 ., , '-' __ l ;-rJ,. .'-J "J. '1tT .+'[ ,.11. "'1- .". '1/'" '···111'1' .•' - r ..1 •• ,~.. ..., ,.,

: I ' '-'" " ' .' I'I':: I :':" Ii:! ; i I : II ";!'!!,: I !I" I "i 'i I Ii I! '1111' J I:! ':! 1'\'i 'Il . 'l: >,' I' : il", ';:1 i' ' :i, ,: I, :!': :>1 \::" ", i'I: I,: til::'" I ,I " I' II ,I I "'II j' 1111 ' 11'1 ) l-fl '. I 'I" 'tt I '" II . I'j I ' 'it ,I I' I, 'I t I' I I "· ~.,,:, 1'::' 01'1',,' ,'li II' 1'/1 11 ',: ',1 I:; l.Ti II I '!'i I ,. I, :i 1::'1:' ... ··I .. p I,,: i: I,:., I;' ,'1 ::::: 'I,': ""\'"I ; ,. P" ",,,,, :1, "~I: "I '1'/:' ill 1i1,1.: i:,;,,!i 'i,~ll!~ '1, 11:' :,:" • ,:1, ',! ,:\::,! :'1' ,i'I':': I: . .:: ,.. : :Y '; \ :.

• ' ::::> I'" '" .', ,. ,. '.' [.; 1 ,·,·t-· •· ..1 "'j , •• •· ..1-··:..k· -1 ~. ·Jrl, ,~••. ).Jl_, , LI· , .., I Ul "I '.. 'I' 'I" :" I,'[' " .1'1"" ," "t' "I'", II: ":1 '''I',"1'\'I' r 'II" '1 1"\'1' ,,:ill; 'I \"1'11 ,I: .:::"\1"11'" "" 'I' I ".\ '"I I' I' t, I" 1 t 'I' II l '\ I, II I 'I' I, I l' 11 I' "I .,1 I' t·, '"., I, I ",I I

" I,' , i::J.: \11, :1, 'ilj":: i;'ll d:., '; ! 1\1.; :1,:II'li' :1' 1-1 'I': i'i1 ;'iJj'lil ':[" ,iii' ';;'Itl'fi ;.: ,lii\I:" ;;1 rl:!::::i"': ~",I ':l'! I :,'I '\ 1 I ~. '1 :, ~ j I : ; : \ I! 'I \ t.1: i 1 ,: Ii:: I q 1n !i lJ i I! :;<~ Ii :, i ~ '~I\.. ; I !::' ': i: I i ~: j d11 ;j j: 1; l' '.' ,: \:' ", I ' I ~

.j p.., '1. 12 , . "'h' jl r 1-·1····· ,., ·,It r t II- I ~l 1.1.. ~ "r."-'" :.J.I • .., '1 _, / .. , , .1 .., ' " ' I ' I:, .,., !!,'. ·II.I'! I I, 'II' \' :I 11 11 ., I'!: 1'1' 'I II ',:., ", J ':" ,',' 'II '11\1 II' it: 1\: , ", I .Ii I" , , . ": '.I ,\1 1

111, , '\ II -! \ '\ J J' I' 'Ill 1 1"11' I I • r.' 'I I , III ,,, I' ,

, W I I" I,d '." ' .. :" 'I"~I'I /11 1 ':,', 'f'" III ,,: 11'/ :,.::Ii Lt· 'P'!' ,It'.: ::1"" I'''''' .I CJ " '.1.', '1:1 ; :: I 'I I," :: I I: ,.' I Ii ", " I: : II I' I:,' "., , . I ,,,:' .1' . . 'I ' , '

, ,~ I I' ," \.", ·1, ., I' "" 1\ .,' ,,' "I '" I, ' • "1""" 'I' ,. " '" I)," I' , ,~ I ',,', jj ,. ,I. I, " ,', 'I' , I' 'I, I" , " j I, , , ," I 'I ',~ ..... , •• , ~,'J • , .'-< 'rr:"'" "'Tft .- _., .... ">'11 --\"""'r:..,-, , l"\" , .~...,"'" ..., ,',. ,... '. , ... l.

, I ,....l , 1"'''' I ' , "It i ill I't'l;: I'; 11'1' 1'1' 'I: il'l\ I" i ",' 'i.[ I':!' !I I'll" "I"';' 'I, I' i' ;tI; : i" I '. , .. ':r-J, I , I I I • ' : I II', 1. 1\ ~ I 1 fI '1 [ I l! I ,I' I : \ I II '. I II I I I 1 I II , !" 'I 1 I I:III ':': ;,I I I ~' " ,: I ",' I", 1':::> I " , ,., " 'I '\ .. ,' II ,. 11 ..1 It·· 'j 'I' J' r' ['" .. '1'1..:.' 1 ... \ 1--1 I !fl' '". 't"I' ... 1 .. '\ ., ..

! " 'j :, '1

11: "II' :\l~ II ,I ':\1 " 11,/ ,'~' !tlt ~ . ','i'L, I It;:,. :: , :.1' ':;~ :,'\ I '1". , ·1:: " ", 1', '; III Ij. : ~ fI,l \ ,', ';" "I ~'1' ,IJI .I:. : ,\,,': "', I: ":' ,! •. ::.,: ., I.: I",', ,1"

?i III ::I-,'r'~,'';!tii'il';';;II-I'! 11I:1ii:: mlr:r: rITj'ij!rrr r~l rl':: ii'::(111: i-\1:I'i':; ';p'ri::,' ':1';:: 'liT;:' '1:':'~',' ," 1";:1""· ~., I' 'i: l:ill':'j.rii :('i1 1\:/ i ji ;' '; ;I,I'IIPI '\' I /Ji l' 'Iii- :.!; t11:1;IlI'I., i::! '!.'!;':.'. 'I'" ::., ", I ,:.: z;:,! :i'l'!!i,'" 'I:, ' ill'I' ,::\ :\:: 'I' ~ '1. 1: t lil:;!1 lii l' ',';!: :;!"f":; i'li'l ;,1,1 :'I'I'i:', 'li t , ""I' '1 1' " 'I I 1

I H ·1·,:· .... '-1 :~I '.:" ~;:I- 'II~" :JjJj .,.~ ....;;1.14L 1UUT, +u. I): ;:1.; ;1:, 1·.:...I~,.t ::~j ' .. ' :, ,.. I .... : .. :.:. :::.,.......

I :' ~ I::, 'j:I,' :;, !\i. :'lil,l,i 'jill 'II; :>,;1 1, '. 'ii!~ill' l.'ifil"1 .J!! :/11 11,11' iiii 1\\:/',':', :;',:::1 '!I::' ~1'1!i'I;:li" i:' ;" : ,. I' 'II"" I 1'1' 1 'I "I '" .I' j 1"1"\ J "'j I' 'j"" I' I, .. , I ' I, I', I I' , I 'I· ' '''I'' \' .. ".,., "1 ]" '''\1'' ·1"" 1'1 . 'll~ " 1" ,. It"'·' ... It' ,"I'" ..... , '." """" '. l'," II' ':':" lilli, 'I, ' :1 .. , , . I' .' .. \, li\ I 'I: " ,i' ": :,1','1'1':1 ," ,',' .': 'I·' : " :i '\'I "I , I I' I I'", IJ)' '. , I· II, ' •• Lit iii' ,II' ,I l' I" j, 1111/ I" <I' .1, t I' 'j"" I I '

' , ... J ' '10 ':r' j.:, "1':1" ~ JJ.:[ll~:.L. ....:: .:~ hi I

r··l 11" ·I j · ·1': itl:;.L. ~r· Ijtr ·r:·tfl:; ·.. :I ..l! "1"i··: 1 II;.;; ....... :,. I' :;

, : I'; I'" \' :. I I':: '\ l' ,I,' , I ' : '. ". 1\ : I '1 'f' " ,I: I II l' \! : 1'1" I' "',' 1... . :, '1' I;' : : ' , . . ' , : • :, I'I 'l, . 'II t '11' II 'J I I I 'I"

jlll t,1 "I 1 • I ,\ II • Ill' 1'1 Illl II I,,, 1"1/ I 'I' I: 'loll "I" 1'1',,", " ,; I'" I' , jll' . " ',,' I"~, I. \ 'II ,'.:1 "I"JII"I '!:f [J. \[1:1",\: ·:;1\··;; I':; :;;'1:':1 .11. ,I' I'" 'ji;.I:: :/ .. ' t.'

1' .. 'I , I"~ I' I' II" I" 'II I' 'I . I II' ' '1 ' . I' '" "1 I III .. " ')' .".. ,'" ",.. ,. "1'",. 'I' I" ,I, '1 i 1'1 ",1 'II 'jllill ; i . I '.,' it!1 I',:' I q"11 ,'I:'illl I,' ': ,Ii: I , ';':1 . ' " 'I" · ... 1' 'I' ,,'

'.", ",I:,. 'I:: 'I I'" '11.1~' I II 'lL!; .... :t;. I~r' + +1 .;1 .:.: "t: ~L, t: •. ~'.: ·~t"·+ .:..1":.\ .:.,.1: 1, :'::I'~'~ .:.:j.'. ,;;:, ,,' .' .,,''. , '", I' I, : l"" 1'11"'; :il) .1\\ ·'.i\11 : 1111'1'1 11 '1.'1 :1,: "I'li .; " j :':, " 'II':,: 1''','111, .:1': i '11,'1 ,I' 111 ;1 'I .. , I II"~

I I " , , ' I I : l I I I ,!' I ! ;! : I: I' 'I I I :; I I I: J I .! , ~ I' I: :; I' ,,:' 'II .'I, 'I" \' I r ':: I : ' ~ II ':' I I: , .: ' : , ' , \". "'1'" 'I""'''' 'I 1'1 ('" .. " I [. I ' ... til' '11·"1. I ... , 1\"1· 1 "., . I I ,... II· ..· 'r l " .'. . , j"

' .1:, ',I \', 1'1 ,. 11 ", ;i'l 'Ii ,'\ :i) ,!/I ',' "1:/1,\', '1',/' ... I;; ,I,. I" '1':': :U" : " ":," ,: 'i. :I,' ::1, ,Ii, ,,"', ' , 1'1,' J " I,,! I, I ' I'll" I I '~ Ifl'l ,." 'I " 111 q'l It .. , L" I, '" I' 't '1'1" '1' ,", '" I'.. 9'- ':1' 'I': 11,1 •.• ··:t I'lll :•.• I., :.• , ~r'l, 1\:' ~:1'111'11'~'" , \.11.:. 't1T';'j": .!. t~.tL ,.... ,... ~. ~' .. 'j:' .,:' ':"1: I:· , . , ' " I I" '" 'II ill II '[I' 1'" II II '\ • 'j1 'I It'" ,I' "" I I' '''''' I" II I' I' II' . I' ." ,II I, "I: I ,. 1!1,:' !11![li!" 'I 11.1"1 : ,I ;/: 'I': ;!~JI:'~fl~1 lj ,I; in: :;11 : I ;l'j I ~!II;1 !li' ;J~lf ;:'1:: 1 I' ;I: ':. ~,:' 11: ,::

" , , , 'I"'" 'I I. , /111" ,,1 ., 1'1 \ .• , 1: 1 "tI ,I), \1 " 1'1" "'l rl;' ." \.1, .. , .... ", • t· '\, •. I .,. ",' I ""I'I I .: I . I I' ,: ,,' i \: ,I ';'II'i': . Ii 'i'I'I:':II, ,I; 1'::.", ::, ., I, ""jl 'i,l' , !I·:I;.· , . .., ,,' ,., . ,: " '

I' ,I I), I' I,' 0 . I I,;, I d "~" ,I'''" <t:" "" I . I , :"! ,'::' I'! . '!'::

• I - , , - , I • t1 :j t I I . I , I I I' 'I I " I'I' I .. ,. ;, 1\': 'I," I ~ I , , ;

" ',,' " " 'I' 11'~'I'1 ""\'1' " , . .,1, "1 . " \"' I.'. ; 110 ',';:1', \1:11100 II, :-,1 200:~1:::: : "~I' 300 II! ' 1',1' 400 'I ;'. '1, 500' ::~ .j~, 600 . I'::·, ,,' 1'1,11 ,I, " I' ,I II , ." . I I II" , " ' 'I ,'I,'" . I'" 'I '1' ' . , 'f 'j' "I" ,. . "': . I , '.' 'I" ';;;1:'" ;Iil i; 1,;q 'ii:i\l,i'!i EHPERATURE 'AT :IMPACTi'(°F);i: 1I i;::·;'i.·I:;:I·I;:~ :i~;i':I'I'" i' '\1"" ,:: 'II : :1; ': ,':1,' II ;:, (I!l 'I, I I, I Ill! ,",', It' 'I"~ .,il :i, I I, ,\" Il

. ". 1 "I' " ., I' "[ '" \, ,I " I "'1 .. , ' , '1' . ,." .,. 1'1"'" I' I'''' .. , I... " •" ' , , II 1,1" I \1, t' 'I '1'1 II 'I 'I ( 111 11 I' ) II 'j l' , 'I ' '" I "I ' ,. I ' ". :v ' I :'11 ,I ".i': ',II',ii II!: !, ,.:,II,ii ::d i ,: Iii' H ';"1": . "! Ii: ':,' ,: :i 'i',: " " .,',.:.

· :'1 1" ",}•. \: I·!' :,;111

:i :' ii'lil'll': :1;'1--:'1'· l'I· Ti !·I:i :lli il';'I'ii:ITI'ilr~ii Il ~1"1:!':I'i; I;:; :;1,11'::'\1:', l":'i\' i": :::.:" ,;: 'j" " "''',I 'I' 'I r I" 1'1 I' I'"~ I I' 111 'I I ,I' \ " ." I 1'1 'I \ 'I" l' ,,"~ .1 I I ( ') 1 "I,, i' I" I 1,',., i '1' i ': 'I: I: , . rl /., ' • " i, Ii1. 1 '1" ,,: 1 ,:.: ,::' I:;' II I ,. 'I ' I': I " I ":":'1"'1 1"':' , : I. I

." I' i " ,I" I " ': i, ,II' /::', :-,'t!I:·I: ,I", :' ,;: I Ii ;r','I"IT :1:, 1/1;"'11\1,; i: lll ,' ,: ".:: I :':\'[., :'" ::::1',: :'

1 • 'l , • , , : ' , , I" J ' , , ' 'I, I • , '; : ;. ~ '_ ,. tI~I~, . ::)< ::.! Iii: FIGURE 8-10 MINll1UM EXPECTED ULLAGE PRESSURE ::: : I:'}:; ,.':; .",· : ::i li;ii~T :j;: :jii FOR SOLID ROCKET MOTOR ~:::i:: ::I:li:' . i:·' i;II':'

::.; :i. '~.:,i:;: .': /, ::lliliFJ' ::"~I;!lil':i!Jl~' i·li,:., >:\ ;,1, ";1: .\: I:,,:~' ,I,. 'I: ' :"1:,1 ':,',:i:: \-:;ih: ;:,:::-: . !:::·,'I':·· "I" ",' 1 ' .. 11 1'1 1'1,ll!" ; ',' 1'\1' "II JI. I ", I 1 I f" "I '1' 'I ' I 'Ill I". ,.... '. ':1 "1':1 1 :; :I', :,:, ;i, .:. ':':\''': :I,j J ,"'J: \::,'\1':' i Iii: ;,11 'I: I .' .;, "i:11 " : i 'I , .' I : 1 "

, I. . :r. . ",':', . . . I'!;:: i I:I " ,,! :. i :: ' :I: :I" i' I '. I: ;; : '1; :- Ii I ,I' I ,~:': ,! ,:- .,:: : I ' I : 'i .: I' ,,'! ; , "', :! , "!":I';::,'t:·, :.:: ;li:':'I':;'I' ';,'r:;:, :1·1;:r,!·;:. il;"I;: :ii~h: I' I [IiI' 'I' j.. ::I·\·· .. ;·: '",,',' \. '11 " .: 'J I

' .. I ,I .. , Ii. , , ,\'1", .. · "'1 . ,1'1' I' .' ",I, .. " 1 "II j . '/ 'I" I ' ',' ',' " . . I ' I ' ., ',' '--,.'-;,:' 1_:_:~I:<;I:.:_:I:,-:.:_,:j.-;-:lL:II-;ji·-';':-";,;i:":i!-'iJ[il!:':;~~JlliIT.r!-~l' ! ; ,~, ilj: II~ <::~';' it) , II < I ,'I J\. I' I I"1'1' . I , II 'I 'J' "Jl' t" II . , 'J1" illlliJll; " lillill-'"Lill!ll'11III' . ,I, ,II' .\' j llillil·1 'Ill \'1"1 j' '~' I ,1 ' 'L' J ' .. J' I I I: :. ," ,'" I" "II: :il :'I'l'!' I! I" I',' ".,:1'" .':!, .;1: ii,': ., ': "I I"~ :,'j , : " I "',1 .' " '" ,'1 \ ,I",l.,_.~" t .J ... i .. J....: .:..Jl .... "'-.~ .........._. l ~ W. ~ L.: -.- ~.J.llJ ~ ..._16 _. ..~..... __ J_........ .... ... _." .__ 1. ..........._

8-45