worm wheel

1. INTRODUCTION

A worm drive is a gear arrangement in which a worm (which is a

gear in the form of a screw) meshes with a worm gear (which is

similar in appearance to a spur gear, and is also called a

worm wheel). The terminology is often confused by imprecise

use of the term worm gear to refer to the worm, the worm gear,

or the worm drive as a unit.

Like other gear arrangements, a worm drive can reduce

rotational speed or allow higher torque to be transmitted. The

image shows a section of a gear box with a worm gear being

driven by a worm. A worm is an example of a screw, one of the

six simple machines

1.1 Explanation of worm wheel:

A gearbox designed using a worm and worm-wheel will be

considerably smaller than one made from plain spur gears and

has its drive axes at 90° to each other. With a single start worm,

for each 360° turn of the worm, the worm-gear advances only

one tooth of the gear. Therefore, regardless of the worm's

size (sensible engineering limits notwithstanding), the gear

ratio is the "size of the worm gear - to - 1". Given a single start

worm, a 20 tooth worm gear will reduce the speed by the ratio

of 20:1. With spur gears, a gear of 12 teeth (the smallest

size permissible, if designed to good engineering practices)

would have to be matched with a 240 tooth gear to achieve the

same ratio of 20:1. Therefore, if the diametrical pitch (DP)

of each gear was the same, then, in terms of the physical size

of the 240 tooth gear to that of the 20 tooth gear, the worm

arrangement is considerably smaller in volume.

http://en.wikipedia.org/wiki/Gear#Spur

http://en.wikipedia.org/wiki/Transmission_(mechanics)

http://en.wikipedia.org/wiki/Simple_machine

http://en.wikipedia.org/wiki/Screw_(simple_machine)

http://en.wikipedia.org/wiki/Torque

http://en.wikipedia.org/wiki/Revolutions_per_minute

http://en.wikipedia.org/wiki/Gear#Spur

http://en.wikipedia.org/wiki/Screw_thread

http://en.wikipedia.org/wiki/Gear

1.2 Types of worm wheel:

There are three different types of gears that can be used in a

worm drive.

The first are non-throated worm gears. These don't have a throat,

or groove, machined around the circumference of either the

worm or worm wheel. The second are single-throated worm gears,

in which the worm wheel is throated. The final type are

double-throated worm gears, which have both gears throated.

This type of gearing can support the highest loading.

An enveloping (hourglass) worm has one or more teeth and

increases in diameter from its middle portion toward both

ends. Double-enveloping wormgearing comprises enveloping worms

mated with fully enveloping wormgears. It is also known as

globoidal wormgearing.

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1.3 Direction of transmission

Unlike with ordinary gear trains, the direction of

transmission (input shaft vs output shaft) is not reversible

when using large reduction ratios, due to the greater friction

involved between the worm and worm-wheel, when usually a

single start (one spiral) worm is used. This can be an

advantage when it is desired to eliminate any possibility of

the output driving the input. If a multistart worm (multiple

spirals) is used then the ratio reduces accordingly and the

braking effect of a worm and worm-gear may need to be discounted

as the gear may be able to drive the worm.

Worm gear configurations in which the gear cannot drive the

worm are said to be self-locking. Whether a worm and gear will be

self-locking depends on the lead angle, the pressure angle,

and the coefficient of friction; however, it is approximately

correct to say that a worm and gear will be self-locking if

the tangent of the lead angle is less than the coefficient of

friction.

1.4 Applications of worm wheel:

In early 20th century automobiles prior to the introduction of

power steering, the effect of a flat or blowout on one of the

front wheels will tend to pull the steering mechanism toward

the side with the flat tire. The employment of a worm screw

reduced this effect. Further development of the worm drive

employs recirculating ball bearings to reduce frictional

forces, allowing some of the steering force to be felt in the

wheel as an aid to vehicle control and greatly reducing wear,

which leads to difficulties in steering precisely.

Worm drives are a compact means of substantially decreasing

speed and increasing torque. Small electric motors are

generally high-speed and low-torque; the addition of a worm

drive increases the range of applications that it may be

suitable for, especially when the worm drive's compactness is

considered.

Worm drives are used in presses, rolling mills, conveying

engineering, mining industry machines, on rudders, and worm

drive saws. In addition, milling heads and rotary tables are

positioned using high-precision duplex worm drives with

adjustable backlash. Worm gears are used on many lift/elevator

and escalator-drive applications due to their compact size and

the non-reversibility of the gear.

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In the era of sailing ships, the introduction of a worm drive

to control the rudder was a significant advance. Prior to its

introduction, a rope drum drive was used to control the

rudder, and rough seas could cause substantial force to be

applied to the rudder, often requiring several men to steer

the vessel, with some drives having two large-diameter wheels

to allow up to four crewmen to operate the rudder.

Figure:1 Truck final drive of the 1930s

Worm drives have been used in a few automotive rear-axle final

drives (although not the differential itself at this time).

They took advantage of the location of the gear being at

either the very top or very bottom of the differential crown

wheel. In the 1910s they were common on trucks; to gain the

most clearance on muddy roads the worm gear was placed on top.

In the 1920s the Stutz firm used them on its cars; to have a

lower floor than its competitors, the gear was located on the

bottom. An example from around 1960 was the Peugeot 404. The

worm gear carries the differential gearing, which protects the

http://en.wikipedia.org/wiki/File:Worm_final_drive_(Manual_of_Driving_and_Maintenance).jpg

vehicle against rollback. This ability has largely fallen from

favour due to the higher-than-necessary reduction ratios.

A more recent exception to this is the Torsen differential,

which uses worms and planetary worm gears in place of the

bevel gearing of conventional open differentials. Torsen

differentials are most prominently featured in the HMMWV and

some commercial Hummer vehicles, and as a center differential

in some all wheel drive systems, such as Audi's quattro. Very

heavy trucks, such as those used to carry aggregates, often

use a worm gear differential for strength. The worm drive is

not as efficient as a hypoid gear, and such trucks invariably

have a very large differential housing, with a correspondingly

large volume of gear oil, to absorb and dissipate the heat

created.

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Worm drives are used as the tuning mechanism for many musical

instruments, including guitars, double-basses, mandolins,

bouzoukis, and many banjos (although most high-end banjos use

planetary gears or friction pegs). A worm drive tuning device

is called a machine head.

Plastic worm drives are often used on small battery-operated

electric motors, to provide an output with a lower angular

velocity (fewer revolutions per minute) than that of the

motor, which operates best at a fairly high speed. This motor-

worm-gear drive system is often used in toys and other small

electrical devices.

A worm drive is used on jubilee-type hose clamps or jubilee

clamps; the tightening screw has a worm thread which engages

with the slots on the clamp band.

Occasionally a worm gear is designed to be run in reverse,

resulting in the output shaft turning much faster than the

input. Examples of this may be seen in some hand-cranked

centrifuges or the wind governor in a musical box.

1.5 Left hand and right hand worm:

A right hand helical gear or right hand worm is one in which

the teeth twist clockwise as they recede from an observer

looking along the axis. The designations, right hand and left

hand, are the same as in the long established practice for

screw threads, both external and internal. Two external

helical gears operating on parallel axes must be of opposite

hand. An internal helical gear and its pinion must be of the

same hand.

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A left hand helical gear or left hand worm is one in which the

teeth twist counter clockwise as they recede from an observer

looking along the axis.

Figure:2 Left hand and right hand of helical gear and worm

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2. LITERATURE SURVEY:

Walker gives a short summary of the origins and the initial

development of worm gears. Archimedes is credited with

introducing the worm gear concept by interlocking a screw,

thread and toothed wheel. An improvement made by cutting a

radius into the tip of the wheel tooth to allow for the worm

thread root diameter was termed a single enveloping gear set. The

clearance allowed a smaller centre distance as the wheel

begins to envelop the worm. Loveless reports that Leonardo

DaVinci developed the double enveloping gear set concept in the 15th

century by varying the worm thread height relative to a radius

about the wheel axis. However, in the same paper Henry Hindley

is largely credited as the first to manufacture gear sets of

this type in the 18thcentury. The reduction in centre

distances provided a more compact system and increased the

length of worm thread flank making contact with the wheel

teeth. This combination resulted in a smaller unit being able

to transmit a higher torque load theoretically.

Vos identifies the CAVEX form as originally developed by

Flender in the early 1950's. This type of worm drive derives

its name from the concave flanks of the worm thread which

differed from conventional convex forms. This improved the

theoretical efficiency and the potential load capacity

relative to an equivalent single enveloping system by

directing more of the force parallel to the worm axis, and

consequently tangential to the wheel rotation.

No scientific basis was defined for worm gear development

until approximately the 1920's. At this point, research into

various design principles for cylindrical worm gear sets was

recorded by Tuplin and Merritt. Work by Merritt and Walker led

to the standardisation of gear production through the initial

development of BS721 in the 1930's. This standard had a latest

revision in 1983 and is still used by industrial gear

designers today to determine the worm and wheel tooth

dimensions.

Analysis of worm gear contact initially involved modelling

worm thread flanks as a series of helices about an axis. These

helices passed through a profile which was determined by the

worm gear type. A detailed analysis for cylindrical gear forms

soon followed from Buckingham in which standard equations were

defined. This derived equations for the geometry of involute,

screw, chased, and milled helicoids worm forms. The analysis

goes on to calculate the 3-dimensional co-ordinates of

theoretical contact lines for the engaging flanks, and

pressure angles relating to the curvature of the thread

profiles which determine

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the line of acting force. Authors such as Dudley and Poritslcy

also made considerable contributions in this area. From these

basic equations it has been possible to develop formulae for

the load capacity, stress limits, and efficiency of a gear

set.

A recent paper from Octrue showed that calculations of load

capacity using these fundamental equations gave a good

correlation with experimental results. This demonstrates the

importance and applicability of such equations to the

operating performance of worm gears.

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2.1 Geometry and nomenclature:

Figure:3 Nomenclature of a single enveloping worm gear

a. The geometry of a worm is similar to that of a power screw.

Rotation of the worm

simulates a linearly advancing involute rack,

b. The geometry of a worm gear is similar to that of a helical

gear, except that the

teeth are curved to envelop the worm.

c. Enveloping the gear gives a greater area of contact but

requires extremely

precise mounting.

1. As with a spur or helical gear, the pitch diameter of a

worm gear is related to its

circular pitch and number of teeth Z by the formula

d Z pπ

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2. When the angle is 90 between the nonintersecting shafts,

the worm lead angle

is equal to the gear helix angle. Angles and have the

same hand.

3. The pitch diameter of a worm is not a function of its

number of threads, Z1.

4. This means that the velocity ratio of a worm gear set is

determined by the ratio of

gear teeth to worm threads; it is not equal to the ratio of

gear and worm

diameters.

ω = Z

ω Z

5. Worm gears usually have at least 24 teeth, and the number

of gear teeth plus

worm threads should be more than 40:

Z1 + Z2 > 40

6. A worm of any pitch diameter can be made with any number of

threads and any

axial pitch.

7. For maximum power transmitting capacity, the pitch diameter

of the worm should

normally be related to the shaft center distance by the

following equation

C0.875 C0.875 in Machine Design II Prof. K.Gopinath & Prof.

M.M.Mayuram

Indian Institute of Technology Madras

8. Integral worms cut directly on the shaft can, of course,

have a smaller diameter

than that of shell worms, which are made separately.

9. Shell worms are bored to slip over the shaft and are driven

by splines, key, or

pin.

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10. Strength considerations seldom permit a shell worm to have

a pitch diameter less

than

d1 = 2.4p + 1.1

11. The face width of the gear should not exceed half the worm

outside diameter.

b ≤ 0.5 da

12. Lead angle λ, Lead L, and worm pitch diameter d1 have the

following relationship

in connection with the screw threads.

tan λ= L (πd)

13. To avoid interference, pressure angles are commonly

related to the worm lead.

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3.0 DESIGN OF WORM GEARING:

Selection Of Gear Box Parameters are given below;

At standared dimensional of worm gearing i=40

FOR i=40 ….from handbook of gear design

i m Z1 dw Γ c

40 5

mm

1 50 5.7106° 125

mm

dg = mzg = 5×40 = 200 mm

3.1 Calculation of output shaft revolutions:

ng= 1500/40 = 37.5 rpm

calculation of input shaft torque is given below;

T1 = H1w = H*30/Лn=150000/4712.38=31.83N.m

1.4 Some Important relations:-

αn=20°

αa =20.09°

3.2 Calculation of worm efficiency:

VW = πXdWXNW

60X1000

= π∗50∗150060∗1000 = 3.927m/s

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Vs = Vw

cosλ

= = 3.947m/s

From Hand Book of Gear Design:-

Form fig . ( 14- 7 ) ……………………… μ = 0.028

η =

= =0.90=90%

3.3 Calculation of output shaft torque:

Tout = T2 = Ti . η .i LET η = 1

= 31.83* 40=1273.24N.m

3.4 Check of power rating:

For Centrefugal- cast bronze ks = 1000

for i = 40………k m = 0.815 … table ( - )

3.927

cos 5 .7

106

Cosα n-µtanγ

Cosαn-µtanγ

Cos 20-0.028tan5.7106

Cos 20+0.028tan

5.7106

for Vs =3.95.….k v 0.285 …table ( - )

fe= ⅔ dw = ⅔ x 50 = 33.3mm or fe=30 less

W G = β.K V. K S. K M. d G 0.8 . fe

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= 0.0131* 1000(200)0.8 *30*0. 815 *0.285

W G = 6327.3N

WF =

=

= 294.692 N

HL=Wf*Vs=294.692*3.95=1164.03343W

Vgt=π ngdg/60=0.9m/s

HO =Wgt*Vgt=6327.3*0.9=5694.57W

H=Ho+Hl=1164.033+5694.57= 6858.6W>5000

3.5 Design of worm:

d a = dw + 2 m = 50+ 2 * 5= 60 mmd d = dw – 2.5 m = 50 - 2.5 * 5 =37.5 mm

3.6 Design of worm wheel:

d g = m x zg = 5 * 40 =200 mm

μ XWw

cos αn. sin λ + μ cos

λ cos T.028* 1273.24

cos 20 . sin 5.7106+..028cos 5.7106

d a = dg + 2m =200 + 2* 5 = 210 mm

d d = dg – 2.5 m = 200 - 2.5 * 5 = 187.5mm

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4. INTRODUCTION OF CATIA:

CATIA V5 R18 (Computer Aided Three Dimensional Interactive

Application)

As the world’s one of the supplier of software,

specifically intended to support a totally Integrated product

development process. Dassault Systems (DDS) in recognized as a

strategic partner which can help a manufacturer to the turn a

process into competitive advance, greater market share and

higher profits and industrial and mechanical design to

functional simulation manufacturing and information

management.

Catia Mechanical design solution will improve our design

productivity. Catia is a suit of programs that are used in

design, analysis and manufacturing of a virually unlimited

range of the product.

“ Feature based” means that we create parts and

assemblies by defining feature like extrusion sweeps, cuts,

holes, round and so on instead of specifying low level

geometry like lines, areas circles. This means that the

designer can think of the computer model at a very high level

and leave all low geometry detail for Catia to figure out.

“Parametric” means that the physical shape of the part as

assembly is driven by the value assigned to the attributes of

its features. We may define or modify a feature dimension or

other attributes at any times. Any changes will automatically

propagate through the model.

“Solid Modeling “ means that the computer model we create

is able to contain all the information that a real solid

object would have. It has volumes and therefore, if you

provide a value for the density of the material it has mass

and inertia.

4.1 Benefits of CATIA:

1. It is much faster and more accurate than any CAD

system.

2. Once design is complete, 2-D and 3-D views are

readily obtainable.

3. The ability to change in late design process is

possible.

4. It provides a very accurate representation of model

specifying all the other dimensions hidden geometry

etc.

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5. It provides a greater flexibility for change, for

example, if we like to change the dimensions in

design assembly, manufacturing etc. will

automatically change.

6. It provides clear 3-D Model which are easy to

visualize or model created and & it Also decrease

the time required for the assembly to a large

extent.

4.2 Applications of CATIA:

Feature and Capabilities

Commonly referred as a 3D product lifecycle

management software suite. CATA support multiple stages of

product development (CAx). The stages range from

conceptualization, through design (CAD) and manufacturing

(CAM) until analysis (CAE), as of 2007 the latest release is

V5 release 18(V5R 18)

4.2.1 Industries using CATIA:

CATIA is widely used through the engineering industry,

especially in the automotive and aerospace sectors, CATIA V4,

VATIA V5 are the dominant systems.

4.2.2. Aerospace:

The Boeing Company used CATIA to develop its 777

airliner, and is currently using CATIA V5 for the 787 series

aircraft. European aerospace giant airbus has been using CATIA

since 2001. In 2006 airbus announced that the reduction of it

airbus 380 using catia. Canadian aircraft maker bombardier

aerospace has done all if its designing on catia.

4.2.3. Automotive:

Automotive Companies that use CATOA to varying degrees

are BMW. Porsche, Daimler, Chrysler, Audi, Volvo, fiat,

Gestamp Automaocian, benteler AG PSA, Pevgcot Citroen,

Penault, Toyota, Honda, ford Scania, Hyundai proton (company),

TATA motors and Mahindra Goodyear uses it in making tires for

automotive and aerospace and also uses a customized CATIA for

its design and development. All automotive companies sue

CATIA for car structures door beams IP supports, bumber beams

root rails, side rails, body components because CATIA is very

good in surface creation and computer representation of

surfaces.

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4.2.4. Ship building:

Dassault system has begun serving shipbuilders with CATIA

V5 release 8. which includes special features useful to

shipbuilders, GD Electric boat used CATIA to design the latest

fast attack submarine class for the united states Navy, the

virgina class, Northrop Grumman Newport news also used CATIA

to design the Gerald R.Ford class of supper carries for us

navy.

4.2.5. Future Implementation:

Dassualt system has announced plans to release CATIA

version 6 (V6) in mid 2008. the new interface allows designer

to work directly with the 3D solid model rather than the

feature based design approach employed in CATIA V5. This

version will also improve the product life cycle management in

a revolutionary way. This concept is called PLm.2. (in

reference of the so called revolution in the internet called

web 2.0)

4.3. Applications of CATIA in modeling:

CATIA Mechanical design solutions offer a modeler a

robust supporting unlimited geometric complex ability and

advanced surfacing capabilities ensuring an accurate

representation of our design.

CATIA automatically embeds design intent into models

providing the flexibility to optimized designs easily and

effectively, as we need.

CATIA offers intelligent product modeling consisting of

familiar parametric features that react predictably to any

change. This enables rapid alternatives all in a logical

engineering environment.

Full associatively guaranties the propagations of design

changes automatically throughout the entire system providing

the update deliverables such as assemblies, drawing, finite

element models, mould process plans and complete manufacturing

data.

CATIA total product representation enables part to part

modeling by capturing all engineering data throughout the

development process, allowing us to fully visualize accurate

product moulds, as they will appear when manufacture.

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4.4 Geometric modeling:

There are number of applications of the CAD software, one

of the most popular applications being geometric modeling.

First of all let us see what is geometric modeling? The

computer compatible mathematical description of the geometric

of this is called as geometric modeling. The CAD software

allows the mathematical description of the object to be

displayed as the image on the monitor of the computer.

4.4.1 Steps for creating the geometric model:

There are three steps in which the designer can create

geometric models by using CAD software, these are:

Creation of basis geometric objects: in the steps the

designer creates basic geometric elements by suing

commands like points, lines and circles.

Transformations of the elements: In the second step the

designer uses commands like achieve scaling, rotation and

other related transformation of the geometric elements.

Creation of the geometric model: During the final step the

designer uses various commands to that cause integration of

the objects or elements of the geometric model to form the

desired shape.

During the process of geometric modeling the computer

converts various commands given from within the CAD software

into mathematical models, stores them as the files; and

finally displays them as the image. The geometric models

created by the designer can open at any time for reviewing,

editing or analysis.

4.4.2. Representation of the geometric models:

Of the various forms of representing the objects in

geometric models, the most basic is wire frames. In this form

the object is displayed by interconnected lines as shown in

the figure below. There are three types of wire frame

geometric modeling, these are: 2D, 2.1/2D and 3D. They have

been described below:

2D: It is stands of two dimensional view and is useful

for flat objects.

2.1/2D: It gives views beyond the 2D view and permits

viewing of 3D object

Ffthat has no sidewall details.

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3D: The three dimension representation allows complete

three-dimensional viewing

Of the model with highly complex geometry. Solid

modeling is the most advanced method of geometric

modeling in three dimensions.

4.5 CATIA user interface:

Below is the layout of the elements of the standard CATIA

application.

A. Menu Commands

B. Specification Tree

C. Window of Active document

D. Filename and extension of current document

E. Icons to maximize/minimize and close window

F. Icon of the active workbench

G. Toolbars specific to the active workbench

H. Standard toolbar

I. Compass

J. Geometry

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Figure no:4 Standard elements of CATIA application

Different types of engineering drawings, construction of

solid models, assemblies of solid parts can be done using

inventor.

Different types of files used are:

1. Part files: CAT Part

2. Assembly files: CAT Product

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4.5.1 Work benches:

Workbenches contain various tools that you may need to

access during your part creation. You can switch between

any primary workbenches using the following two ways:

Figure no:5 Work benches

A. Use the Start Menu.

B. Click File >New to create a new document with a

particular file type. The associated workbench

automatically launches.

The parts of the major assembly is treated as individual

geometric model , which is modeled individually in separate

file .All the parts are previously planned & generated feature

by feature to construct full model.

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Generally all CAD models are generated in the same passion

given bellow :

: Enter CAD

environment by clicking, later into part

designing

mode to construct model.

: Select plane as

basic reference.

: Enter sketcher

mode.

In sketcher mode:

: Tool used to create 2-d basic

structure of part using line, circle etc

: Tool used

for editing of created geometry termed

as

operation

: Tool used for

Dimensioning, referencing.

This helps creating

parametric relation.

: Its external feature to view

geometry in & out

: Tool used to exit sketcher mode after creating

geometry.

Sketch Based Feature:

Pad : On exit of sketcher mode the feature is to

be padded .( adding

material )

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Pocket: On creation of basic structure

further pocket

has to be created (removing material )

Revolve: Around axis the material is

revolved, the

structure should has same profile

around axis.

Rib: sweeping uniform profile along trajectory

(adding material)

Slot: sweeping uniform profile along trajectory

(removing material)

Loft: Sweeping non-uniform/uniform profile

on different

plane along linear/non-linear trajectory

:

Its 3d creation of features creates chamfer,

rad

ius, draft, shell

: :

Its tool used to move geometry, mirror, pattern, scaling in 3d

environment on creation of individual parts in

separate files,

Assembly environment: In assembly environment the

parts are recalled & constrained.

Product structure tool: To recall existing

components already modeled.

:Assembling respective parts by

mean of constraints

Update: updating the made constrains.

Additional features are: Exploded View, snap

shots, clash analyzing numbering, bill of

material. Etc

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Finally creating draft for individual parts &

assembly with possible details

The parts of the major assembly is treated as individual

geometric model , which is modeled individually in separate

file .All the parts are previously planned & generated feature

by feature to construct full model

Generally all CAD models are generated in the same passion

given below:

: Enter CAD environment by clicking, later

into part designing

mode to construct model.

: Select plane as basic reference.

: Enter sketcher mode.

In sketcher mode:

: Tool used

to create 2-d basic structure of

part using

line, circle etc

: Tool used for editing of created

geometry termed as operation

: Tool used for Dimensioning,

referencing. This helps creating

parametric relation.

: Its external feature to view

geometry in & out

:Tool used to exit sketcher mode after creating geometry.

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Sketch Based Feature:

Pad: On exit of sketcher mode the feature is to

be padded. (Adding material)

Pocket: On creation of basic structure further

pocket has to be created

(removing material)

Revolve: Around axis the material is revolved,

the structure

should have same profile around axis.

Rib: sweeping uniform profile along trajectory

(adding material)

Slot: sweeping uniform profile along trajectory

(removing material)

Loft: Sweeping non-uniform/uniform profile on

different plane along linear/nonlinear

Trajectory

: Its 3d

creation of features creates chamfer,

radius

, draft shell, thread.

: This tool is used to move

geometry, mirror, pattern,

scali

ng in 3d environment.

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5.0 Introduction of ANSYS:

This Tutorial will use a readymade file to speed up the

learning process for the student. This file is provided in

Parasolid format. The intention of this tutorial is to get the

student to run a straight forward simulation. By the end of

this tutorial a check list for the required procedure can be

formulated by the student. ANSYS as a software is made to be

user-friendly and simplified as much

as possible with lots of interface options to keep the

user as much as possible from the hectic side of

programming and debugging process.

Why is it that such a simple model is used?

During this tutorial a simple geometry is used, the objective

of that is that the student masters the steps to get to run a

simple simulation, once that’s done the student can model any

kind of geometry he sees necessary for his studied case.

Step1: Launch ANSYS ,by going to the start-up menu and double

clicking on workbench file in the ANSYS 13.0 folder.

Figure no:6 Step:1 in ANSYS

(A reminder that not all lab machines have the

ANSYS software installed on them.)

Step2: Once the program is launched it should look like as

shown below. Go to Analysis Systems;

Fluid Flow (CFX) and double click.

Figure7: Step:2 in ANSYS

(You might have to wait a bit till ANSYS gets running, the

student is encouraged to use the provided help with the

software, it has lots of useful hints here and there.)

Step3: Next Double click on the Geometry. This stage is for

getting the required geometry read into the software, note

that there is a blue question mark icon beside the geometry

text. Looking at the bottom of the window you will see two

windows one having the title of Messages, this title confirms

that the imported geometry has no problems with it, the next

window has the title Progress and

that is necessary to prove that state of the progress and if

there is a problem it will state the problem.


(At the moment the illustration are a bit

simplified for the user and will get complex with

time.)

Step4: Once ANSYS Workbench window is active you will get a

window asking to specify working units for the model dimension

chose meters and press ok. For the user this step might seem

secondary in importance but as a matter of fact it’s of great

importance, because at later stages you will have to specify

the box size (discrete element dimension). Box size dimension

leads to finer mesh, the finer the used mesh is the more

accurate is the captured data. The captured data term refers

to the fluid flow structures.


(Depending on your studied case the selection of

serial or parallel is taken, also depending on the

hardware provided in the computer lab dual core or

quad core etc.)

Step5: Go to file and choose Import External Geometry File…. .


(You can model your geometry using the sketching tools

provided with Design Modeler.)

Step 6: A window having a title open will be visible to

the user, choose File type

Parasolid(*x_t;*xmt_txt;*x_b;*xmt_bin) then go to the

folder that has the required file .


(There are lots of software that are used to generate meshes,

depending on the software used the file extension text would be,

in our case we are using SolidWorks to generate the mesh and then

exporting it in Parasolid format. A question comes to the mind of

the student why do I have to specify the file extension. The

answer is that each mesh generation software has its own structure

in its generated data sets. A simple example:)

Step7: Looking at the DesigModeler window, we can’t see the

imported geometry yet, what is required next is to press on

the generate icon that is represented by a yellow thunder

icon.


(The DesignModeler will read in the imported data file, and

will construct the required mesh.Step7: The imported Geometry

Domain should look something like this, still that doesn’t

give any hints to the user, relating to the inner structure of

the domain.)

Step8: Go to the view and choose wire frame as shown below;


(go to view and chose wireframe)

Step9: Go to the view and the inner structure of the domain as

shown below;


(This step is necessary to view the inner structure of

the domain.)

Step9(a): Mouse options are shown below;

Figure15.1: Step:9(a) in ANSYS

(Once the student gets to this stage, that means he has

finished from the Design Modeler and has to proceed to the

Meshing part)


(Rotate the view and check that the Geometry satisfies the

design requirements.)

Step 9(b): Go to the workbench and check that there is a green

tick sign beside the Geometry and then double click on the

Mesh Icon.

Figure15.3: Step:9(b) in ANSYS

(Congratulations you have finished from DesignModeler and now

have started with the Meshing part.)

Step 10: The Meshing part of the project has started,

notice that beside the Mesh there is a yellow thunder

icon.


(The scale shown at the bottom helps you make the right

decision on the box sizing, sothat we can see that the

largest value on the scale is 0.200(m) which means we have to

choose a value less than 0.050(m).)

Step 10(a): right click on Mesh and chose Insert and then

chose Method


(At this stage we come to the point where we have to choose

what kind of mesh are we going to use wither regular or

irregular or etc.)

Step 10(b): click on the positive sign beside the Mesh you

should get a tree sub branch have automatic Method using the

left button click on the grey box domain, as a result it

should by highlighted in green, then you see that the geometry

text is highlighted in blue press the apply.

Figure16.2: Step:10(b) in ANSYS

(Choose the parallel option in the projection mode, which

will come handy later on, when you want to use the

measure command or choosing the appropriate slice plane

for your study.)

Step 11: go to method and choose Tetrahedrons.


(Now that you have specified the mesh properties, you can

proceed to the next step.)

Step12: press the Update icon and then press on the

Generate Mesh icon.


(For our case we will want to now the dimensions of the

inflow section of the pipe.)

Step13: click on mesh, now it’s visible to the user the

generated mesh.


(Click on the middle button to rotate the view to inspect

your mesh.)

Step14: Go to work bench, you will see there is a

green tick beside the mesh congratulations you can

now proceed to the setup.


(Check the messages window if there are any errors you will

have to go back in steps and check where you went wrong)

Project

First SavedSaturday, September

20, 2014

Last Saved Saturday, September

20, 2014

Product Version 14.0 Release

Save Project Before

SolutionNo

Save Project After

SolutionNo

Contents

Units

Model (A4)

o Geometry

Parts

o Coordinate Systems

o Connections

o Mesh

o Static Structural (A5)

Analysis Settings

Loads

Solution (A6)

Solution Information

Results

Material Data

o Gray Cast Iron

o Structural Steel

Units

TABLE

1

Unit SystemMetric (mm, kg, N, s, mV, mA)

Degrees rad/s Celsius

Angle Degrees

Rotational

Velocityrad/s

Temperature Celsius

Model (A4)

Geometry

TABLE 2

Model (A4) > Geometry

Object Name Geometry

State Fully Defined

Definition

SourceC:\Users\sanju\Desktop\

worm ass.igs

Type Iges

Length Unit Meters

Element Control Program Controlled

Display Style Body Color

Bounding Box

Length X 183.39 mm

Length Y 215.7 mm

Length Z 48.001 mm

Properties

Volume 74736 mm³

Mass 0.5381 kg

Scale Factor Value 1.

Statistics

Bodies 2

Active Bodies 1

Nodes 5767

Elements 3088

Mesh Metric None

Basic Geometry Options

Solid Bodies Yes

Surface Bodies Yes

Line Bodies No

Parameters Yes

Parameter Key DS

Attributes No

Named Selections No

Material Properties Yes

Advanced Geometry Options

Use Associativity Yes

Coordinate Systems No

Reader Mode Saves

Updated FileNo

Use Instances Yes

Smart CAD Update No

Attach File Via Temp

FileYes

Temporary DirectoryC:\Users\sanju\AppData\

Local\Temp

Analysis Type 3-D

Mixed Import Resolution None

Decompose Disjoint Faces Yes

Enclosure and Symmetry

ProcessingYes

TABLE 3

Model (A4) > Geometry > Parts

Object Name Part 1 Part 2

State Meshed Suppressed

Graphics Properties

Visible Yes No

Transparency 1

Definition

Suppressed No Yes

Stiffness

BehaviorFlexible

Coordinate

System

Default Coordinate

System

Reference

TemperatureBy Environment

Material

AssignmentGray Cast

Iron

Structural

Steel

Nonlinear

EffectsYes

Thermal Strain

EffectsYes

Bounding Box

Length X 60. mm 183.39 mm

Length Y 48.002 mm 183.39 mm

Length Z 48.001 mm 20.001 mm

Properties

Volume 74736 mm³3.9619e+005

mm³

Mass 0.5381 kg 3.1101 kg

Centroid X1.842e-002

mm

7.5693e-007

mm

Centroid Y 100.3 mm1.6878e-006

mm

Centroid Z2.4372e-003

mm

2.2837e-005

mm

Moment of 118.31 5058.8

Inertia Ip1 kg·mm² kg·mm²

Moment of

Inertia Ip2

213.23

kg·mm²

5058.8

kg·mm²

Moment of

Inertia Ip3

213.71

kg·mm²

9910.3

kg·mm²

Statistics

Nodes 5767 0

Elements 3088 0

Mesh Metric None

Coordinate Systems

TABLE 4

Model (A4) > Coordinate Systems > Coordinate System

Object NameGlobal Coordinate

System

State Fully Defined

Definition

Type Cartesian

Coordinate

System ID0.

Origin

Origin X 0. mm

Origin Y 0. mm

Origin Z 0. mm

Directional Vectors

X Axis Data [ 1. 0. 0. ]

Y Axis Data [ 0. 1. 0. ]

Z Axis Data [ 0. 0. 1. ]

Connections

TABLE 5

Model (A4) > Connections

Object Name Connections

StateFully

Defined

Auto Detection

Generate Automatic Connection

On RefreshYes

Transparency

Enabled Yes

Mesh

TABLE 6

Model (A4) > Mesh

Object Name Mesh

State Solved

Defaults

Physics Preference Mechanical

Relevance 0

Sizing

Use Advanced Size

FunctionOff

Relevance Center Medium

Element Size Default

Initial Size Seed Active Assembly

Smoothing Medium

Transition Fast

Span Angle Center Coarse

Minimum Edge Length 0.256690 mm

Inflation

Use Automatic Inflation None

Inflation OptionSmooth

Transition

Transition Ratio 0.272

Maximum Layers 5

Growth Rate 1.2

Inflation Algorithm Pre

View Advanced Options No

Patch Conforming Options

Triangle Surface MesherProgram

Controlled

Advanced

Shape CheckingStandard

Mechanical

Element Midside NodesProgram

Controlled

Straight Sided Elements No

Number of Retries Default (4)

Extra Retries For

AssemblyYes

Rigid Body BehaviorDimensionally

Reduced

Mesh Morphing Disabled

Defeaturing

Pinch Tolerance Please Define

Generate Pinch on

RefreshNo

Automatic Mesh Based

DefeaturingOn

Defeaturing Tolerance Default

Statistics

Nodes 5767

Elements 3088

Mesh Metric None

Static Structural (A5)

TABLE 7

Model (A4) > Analysis

Object NameStatic Structural

(A5)

State Solved

Definition

Physics Type Structural

Analysis TypeStatic

Structural

Solver TargetMechanical

APDL

Options

Environment

Temperature22. °C

Generate Input

OnlyNo

TABLE 8

Model (A4) > Static Structural (A5) > Analysis Settings

Object Name Analysis Settings

State Fully Defined

Step Controls

Number Of

Steps1.

Current Step

Number1.

Step End Time 1. s

Auto Time

SteppingProgram Controlled

Solver Controls

Solver Type Program Controlled

Weak Springs Program Controlled

Large

DeflectionOff

Inertia

ReliefOff

Restart Controls

Generate

Restart

Points

Program Controlled

Retain Files

After Full

Solve

No

Nonlinear Controls

Force

ConvergenceProgram Controlled

Moment


Displacement Program Controlled

Convergence

Rotation


Line Search Program Controlled

Stabilization Off

Output Controls

Stress Yes

Strain Yes

Nodal Forces No

Contact

MiscellaneousNo

General

MiscellaneousNo

Calculate

Results AtAll Time Points

Max Number of

Result SetsProgram Controlled

Analysis Data Management

Solver Files

Directory

C:\Users\sanju\AppData\Local\Temp\WB_SANJU-

PC_5892_2\unsaved_project_files\dp0\SYS\MECH\

Future

AnalysisNone

Scratch

Solver Files

Directory

Save MAPDL db No

Delete

Unneeded

Files

Yes

Nonlinear No

Solution

Solver Units Active System

Solver Unit

Systemnmm

TABLE 9

Model (A4) > Static Structural (A5) > Loads

Object NameFixed

SupportForce

State Fully Defined

Scope

Scoping

MethodGeometry Selection

Geometry 2 Faces 1 Face

Definition

TypeFixed

SupportForce

Suppressed No

Define By Vector

Magnitude 10. N

(ramped)

Direction Defined

FIGURE 1

Model (A4) > Static Structural (A5) > Force

Solution (A6)

TABLE 10

Model (A4) > Static Structural (A5) > Solution

Object NameSolution

(A6)

State Solved

Adaptive Mesh Refinement

Max Refinement

Loops1.

Refinement 2.

Depth

Information

Status Done

TABLE 11

Model (A4) > Static Structural (A5) > Solution (A6) > Solution

Information

Object NameSolution

Information

State Solved

Solution Information

Solution Output Solver Output

Newton-Raphson

Residuals0

Update Interval 2.5 s

Display Points All

FE Connection Visibility

Activate Visibility Yes

DisplayAll FE

Connectors

Draw Connections

Attached ToAll Nodes

Line ColorConnection

Type

Visible on Results No

Line Thickness Single

Display Type Lines

TABLE 12

Model (A4) > Static Structural (A5) > Solution (A6) > Results

Object Name Total Directional Equivalent Stress Normal Stress

Deformation Deformation

State Solved

Scope

Scoping

MethodGeometry Selection

Geometry All Bodies

Definition

Type

Total

Deformatio

n

Directional

Deformation

Equivalent

(von-Mises)

Stress

Normal

Stress

By Time

Display

TimeLast

Calculate

Time

History

Yes

Identifier

Suppressed No

Orientation X Axis X Axis

Coordinate

System

Global

Coordinate

System

Global

Coordinate

System

Results

Minimum 0. mm-2.2233e-006

mm

6.5573e-005

MPa

-4.7707e-002

MPa

Maximum2.6183e-

006 mm

5.0926e-007

mm

2.9703e-002

MPa

1.7056e-002

MPa

Information

Time 1. s

Load Step 1

Substep 1

Iteration

Number1

Integration Point Results

Display

Option Averaged

FIGURE 2

Model (A4) > Static Structural (A5) > Solution (A6) > Total

Deformation > Figure

FIGURE 3

Model (A4) > Static Structural (A5) > Solution (A6) >

Directional Deformation > Figure

FIGURE 4

Model (A4) > Static Structural (A5) > Solution (A6) >

Equivalent Stress > Figure

FIGURE 5

Model (A4) > Static Structural (A5) > Solution (A6) > Normal

Stress > Figure

Material Data

Gray Cast Iron

TABLE 13

Gray Cast Iron > Constants

Density 7.2e-006 kg mm^-3

Coefficient of Thermal

Expansion1.1e-005 C^-1

Specific Heat4.47e+005 mJ kg^-

1 C^-1

Thermal Conductivity 5.2e-002 W mm^-1

C^-1

Resistivity 9.6e-005 ohm mm

TABLE 14

Gray Cast Iron > Compressive Ultimate Strength

Compressive Ultimate

Strength MPa

820

TABLE 15

Gray Cast Iron > Compressive Yield Strength

Compressive Yield

Strength MPa

0

TABLE 16

Gray Cast Iron > Tensile Yield Strength

Tensile Yield

Strength MPa

0

TABLE 17

Gray Cast Iron > Tensile Ultimate Strength

Tensile Ultimate

Strength MPa

240

TABLE 18

Gray Cast Iron > Isotropic Secant Coefficient of Thermal

Expansion

Reference

Temperature C

22

TABLE 19

Gray Cast Iron > Isotropic Elasticity

Temperatu

re C

Young's

Modulus MPa

Poisson's

Ratio

Bulk Modulus

MPa

Shear Modulus

MPa

1.1e+005 0.28 83333 42969

TABLE 20

Gray Cast Iron > Isotropic Relative Permeability

Relative

Permeability

10000

Structural Steel

TABLE 21

Structural Steel > Constants

Density7.85e-006 kg mm^-

3

Coefficient of Thermal

Expansion1.2e-005 C^-1

Specific Heat4.34e+005 mJ kg^-

1 C^-1

Thermal Conductivity6.05e-002 W mm^-1

C^-1

Resistivity 1.7e-004 ohm mm

TABLE 22

Structural Steel > Compressive Ultimate Strength

Compressive Ultimate

Strength MPa

0

TABLE 23

Structural Steel > Compressive Yield Strength

Compressive Yield

Strength MPa

250

TABLE 24

Structural Steel > Tensile Yield Strength

Tensile Yield

Strength MPa

250

TABLE 25

Structural Steel > Tensile Ultimate Strength

Tensile Ultimate

Strength MPa

460

TABLE 26

Structural Steel > Isotropic Secant Coefficient of Thermal

Expansion

Reference

Temperature C

22

TABLE 27

Structural Steel > Alternating Stress Mean Stress

Alternating

Stress MPa

Cycle

s

Mean Stress

MPa

3999 10 0

2827 20 0

1896 50 0

1413 100 0

1069 200 0

441 2000 0

262 10000 0

214 20000 0

1381.e+0

050

1142.e+0

050

86.21.e+0

060

TABLE 28

Structural Steel > Strain-Life Parameters

Strength

Coefficien

t MPa

Strength

Exponent

Ductility

Coefficie

nt

Ductilit

y

Exponent

Cyclic

Strength

Coefficient

MPa

Cyclic

Strain

Hardening

Exponent

920 -0.106 0.213 -0.47 1000 0.2

TABLE 29

Structural Steel > Isotropic Elasticity

Temperatu

re C

Young's

Modulus MPa

Poisson's

Ratio

Bulk Modulus

MPa

Shear

Modulus MPa

2.e+005 0.3 1.6667e+005 76923

TABLE 30

Structural Steel > Isotropic Relative Permeability

Relative

Permeability

10000

worm wheel

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