Queensland University of Technology - Science and Engineering Faculty

EGB111 – Foundations of Engineering DesignProject Brief - 2015This project brief has been prepared following discussions with your client. The final CRA assessment for this group project is appraised against this documentation.

Figure 1 - Overview of the testing board

1. Project ObjectiveDesign and construct a model crane to move an object from the lower pedestal at location A and relocate it onto the higher pedestal at location B.The crane must be designed as per the specifications supplied in this project brief.

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2. The ObjectThe object to be relocated is a statue with a mass of 0.5 kg. Refer to Figure 2 for detailed dimensions of the statue. In order to ensure the statue is not damaged, it must be carefully lifted, carefully placed down and not dragged at anystage of the move. The lifting device will also be tested witha 1.5 kg object to determine if the device has been designed with an appropriate safety factor and not overdesigned. Note that when additional weights are added to the 0.5 kg mass, theoverall width of the statue may approach 100mm.

Figure 2 - The 0.5kg Mass

3. The Testing SiteTesting of the lifting device will be conducted on a scaled down version of Queens Park (next to the Treasury Casino). All

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dimensions and the location of pedestals of this testing boardcan be found in Appendix 1 – Site Dimensions. The initial position of the object is on Pedestal A, which is 50 mm high. The final position for the object is on Pedestal B, which is 100 mm high.

4. The Lifting DeviceThe device including any ballast must be in contact with the ground, and be free standing and stable when no load is attached. Reducing the weight of the device with lighter than air attachments is not permitted. The lifting device can be constructed of any material. Keep in mind that factors such asweight and strength will affect performance of the device, while factors such as cost and constructability will influenceyour ability to complete the build.

4.1 FootingsThe device can either be fixed to the testing board at point Cor be a non-fixed design. It is advisable to ensure you view the actual testing board prior to finalising your design.

Fixed DeviceA fixed device will be connected via 4 x M6 hold-down boltholes at point C on the testing board. For a fixed device, the grounded area must be no greater than 150 mm x 150mm.

Unfixed DeviceIf the device is unfixed, it may make contact with the board at any point, however, it cannot touch the pedestals or any object outside the board.

4.2 Structural Sub-SystemThe horizontal arm (jib) must be a determinant truss. During testing, it must support the 0.5 kg load. For optimal marks, this truss should fail when a 1.5 kg load is applied, to show that no overdesign is present. The rest of the structure can be of any design and may be overdesigned.

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4.3 Electrical Sub-SystemFor the official testing, power for the device must be drawn from a single DC power supply supplied by QUT. This power supply provides fixed 24 VDC at 3 Amps maximum. During testing, the power the device draws from the power supply willbe measured. The peak power measurement (ignoring initial peaks) must be under 25 Watts. For optimal marks, the peak power measurement (ignoring initial peaks) should be under 10 Watts. The current must be limited so that the device cannot draw more than the specified power.The kinetic energy of the device must come from electrical energy directly from the power supply on testing day. Electrical energy can be converted into other forms and subsequently into kinetic energy, but the initial source of energy must be electrical. This means that the device cannot use pre-stored electrical energy or pre-compressed springs. Potential energy stored in weights cannot be used to move the device.Wired hand controls are required. They will not be included when measuring the weight of the device.

4.4 Mechanical Sub-SystemThe crane will require certain mechanical elements in order toensure effective movement of the statue. Gearboxes will be required to be attached to motors to move the mass and a bearing system will be required to ensure smooth rotation of the jib.

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5. Device Testing

5.1 ProcedureEach team will be given a 10 minute period to test the device on one of the testing boards during testing day. Multiple attempts are permitted within the 10 minute testing period. The device will firstly be weighed and then its ability to move the 0.5 kg mass will be assessed. During the move, time of relocation and peak power consumption will be measured.

General RulesYou may manually attach the lifting hook to the statue prior to the beginning of the test operation. You are not required to remove the hook, either manually or remotely, at the completion of the operation.You cannot manually assist your motor(s) to overcome static friction or other stall conditions unless directed by your assessor to assist in progressing the operation.You cannot touch the device at all during the move. You may only manipulate electrical switches to perform the operation.

TimingThe timing of the task will begin when nominated and will end when the load is fully supported at Pedestal B. Both prior to commencement and at completion of the testing procedure, the respective pedestal must completely support the statue weight.

PowerThe power supply will be set up to provide fixed 24 VDC at 3 Amps maximum.

StructureIf the device completes this move successfully, a 1.5 kg weight will be applied to the device in turn at its starting and final positions to ensure the device is not structurally overdesigned. Structural failure is achieved when a clear failure of a truss member or joint occurs.

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5.2 Assessment CriteriaThe following checklist will be used to determine the performance grade of the device. The factors being assessed are the total weight of the device including any counterweights, time taken to complete the move, peak power consumption and appropriate structural design.Grade 2 – must achieve the following criterion

The crane features complete structural and electromechanical systems

Grade 3 – must achieve the following criterion The crane must be fully operational while no load is

attached (must lift and rotate)

Grade 4 – must achieve ALL OF the following pass requirements in addition to the prior criteria

Completes the move in under 2.5 minutes Total weight of the device is less than 4 kg Peak running power is less than 25 Watts Complies with all specifications given in the project

brief

Grade 5 – must achieve TWO of the optimal requirements in addition to the Grade 4 criteriaGrade 6 – must achieve THREE of the optimal requirements in addition to the Grade 4 criteriaGrade 7 – must achieve ALL FOUR of the optimal requirements inaddition to the Grade 4 criteriaOptimal Requirements:

The crane weighs under 1.5kg Time of relocation under 1 minute Peak running power less than 10 Watts The main truss is designed with a factor of safety of

between 1 and 3

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Appendix 1 - Site Dimensions

Note: Grass sections are approximately 4 mm higher than the paved sections

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