RECENT ASSIGNMENT

Question 1 (80/200 marks)
Question 1 Problem Statement
Figure 1 shows an impression of one of many lifting arrangements produced and used at a steel fabrication workshop. It was manufactured to lift a maximum of 150 kg and due to a product line change, it needs to be modified to lift a maximum mass of 175 kg and extend the crane arm further 0.5 m as shown in Figure 2. Furthermore, the lifting mechanism at the loading points (A) needs to be changed to a motor-driven winch which weighs 26kg. This motor driven winch can lift a load of 175 kg at a constant acceleration of up to 0.05 m/s2. Due to these changes, the factory manager needs to know whether the present lifting crane can be modified as quickly as possible using only the (left over) 4m long piece of pipe 2 (70 mm outer dia. and 5 mm thickness) that had been purchased to manufacture the original lifting cranes. Your task is to provide a proposal to the Manager for the extended crane configuration including an appropriate detailed analysis of proposed configuration/modifications.
The required design constraints are as follows:
Function of the existing cranes:
A loading block is attached as shown to Pipe 2 at the end A. The load will be raised from the floor level to a height of 4 metres. Do not consider the geometry of the load at this stage. Pipe 1 encased (smooth fit) a part of pipe2 and rigidly attached to the same WC500 440 column of a workshop building at B in order to reduce the high bending stresses acting at on the end B of Pipe 1.
Available materials for modifications:
Materials: A 4m long piece of Pipe 2. (All pipes are steel with the Ultimate Strength of 320 MPa, Yield Strength 280 MPa, Shear Strength 248 MPa, E= 200 GPa, Poisson’s ratio =0.3, Density 7880 kg/m3). Please note that it is expected to use 0.5 m of the 4m long pipe-length to weld on to the end A to extend the total crane arm length to 2m. The attachments of new pieces to the existing crane is only by means of welding.
Design Criteria:
Part 1-Analysis of crane’s new configuration i.e. only with the proposed 0.5 m extension and the new operational loads and other new lifting arrangements - Do not use FEA software for this task.
1. Start with the analysis of existing crane arrangement for proposed rated load of 175 kg (+ 25% rated capacity) with the proposed 0.5 m extension and other lifting attachments.
2. Only hand calculations using fundamental formulas will be accepted. Use your fundamental knowledge in Stress Analysis (pre-requisite MEC2402 or equivalent). Strictly, do not use design formulas provided in design calculations, software or standards. Use suitable assumptions where required.
3. You have to list all your assumptions and highlight them in the report. You are free to make justifiable assumptions to resolve statically indeterminate situations or problems. You also need to write and identify the parameters used in your fundamental equations.
4. Provide suitably neat hand sketches where necessary and the final proposal must be sketched clearly. CAD packages can be used to present your design, but clearly define features with comments where appropriate. You are free to assume general engineering workshop processes are available for implementation of your modifications.
5. Provide your calculated results (stresses etc) using an appropriate presentation method (tabulate, list etc)
Part 2 – If you have identified significantly high stresses in the new crane structure (i.e 170 MPa or deflection 20 mm) then propose your modifications such as supports, braces etc. only using the leftover pipe 2 piece (approx.3.5 m long). With your proposed modifications re-do part 1 items 1-5 (analysis and results).
Design/Modification Limitations:
The modification will not extend in to the marked “Work Space” are in the Figure 2. The height and reach of the loading point is to remain the same (as Figure 2). Original parts must remain and you are allowed additions such as corner plates, bracing , casings, ribs, enclosures for reinforcing etc. Due to frequent extreme overloading of crane by factory floor workers, the stress levels of major structural components of crane needs to be kept under 170 MPa wherever possible. Also you need to limit the vertical and horizontal displacement at the loading point less than 20 mm.
Part 3 - (Use Creo 3.0 Simulate for FEA analysis)
Create a suitable model with beam elements and perform relevant FEA analysis for:
1. Existing crane arrangement with rated load
2. Extended crane described in Part 1 with increased rated loads and other accessories
3. Extended and modified (with your proposed braces & supports) as described in Part 2 with increased rated loads and other accessories
Your need to provide usual FEA details i.e. complete picture of FEA model showing constraints, applied loads, number of elements and nodes, analysis type, element types, material properties, and other related details and you need to justify your FEA analysis based on manual calculations. Also:
• Tabulate necessary/critical stress levels and location for each case separately. You need only to show necessary stress/strain/displacement plots from Creo2.0 to justify your analysis.
• A detailed note/Conclusions on your design/modification.
Figure1. Existing Crane arrangement
Question 2 (80/200 marks)
Question 2 Problem Statement
Figure 3 shows a laterally loaded steel beam arrangement.
Your task:
• Sketch shear force and bending moment diagrams and estimate maximum bending and shear stresses acting on the beam using your knowledge in beam analysis. (Please note that this beam problem is statically indeterminate. However, you can solve this problem using method of superposition.
• Also using fundamental relationship deduce an equation for lateral deflection of beam AB. Using the deflection equation deduce the lateral deflection at the mid-point of beam C. (E=200 GPa, Poisson’s ratio =0.3)
• Perform a 2D FEA (Beam analysis) on Creo 3.0 Simulate and compare FEA results and manually determined values for reactions at A and B and the deflection at mid-point of the beam C. (Tabulate your results) and provide usual FEA details in your report.
Beam Section (Nominal linear mass 18 kg/m)

Figure 3. A Laterally loaded steel beam
Question 3 (40/200 marks)
Question 3 Problem Statement
Perform a design analysis for a combination spanner (chose a size from the range 12mm - 24 mm). A representative example is shown in Figure 4.
Figure 4: A combination spanners
(You will need to find appropriate dimensions for your chosen spanner)
Your task:
1. Determine design parameters relevant to the spanner such as materials, nominal operational force/moment/torque, details of design practices
2. Perform your analysis on both ends of the spanner.
3. Create your own geometrical design for the selected spanner size.
4. Perform necessary hand calculations (at least three random calculations) to support your design
5. Create a suitable solid model for the spanner in Creo3.0 and perform an FEA analysis
6. Provide a report which includes your design, design parameters and hand calculations. The report must show the details of your FEA including appropriate stress/strain plots and a comparison of hand calculations with FEA results.