RECENT ASSIGNMENT

University of Wollongong
Faculty of Engineering and Information Sciences
MECH419/928
Assignment 1 (20%) Autumn Session – 2017
Due Friday week 7 13 April (Group project of max 2 members)
Rules (Please read):
1. The assignment may be completed individually or by a group (of maximum 2 members). The group formation is your own responsibility. Members may be from the same or different tutorial groups.
2. The assignment is due in week 7 (Thursday 13 April) and submitted to EIS Central using the barcoded sheet (see subject outline under assignment submission). Late submission will incur penalty as described in the subject outline. Copying other works or having someone else to do the works will result in severe penalty and in serious case will be referred to the school assessment committee (with recommendation of zero mark or TF, and expulsion from the university). Welcome to ask me if you are unsure or consult the university policies regarding copying (see subject outline under University and Faculty Policies).
3. As this assignment is considered as engineering project undertaken by group of engineers, group synergy and team work are part of the learning. So if the assignment is completed by group, include statement indicating the effort or contribution to the assignment by each member and describe how you group work together to solve the problem.
4. The MATLAB script files and function files must be included as appendix in the report. Actual files are not needed, but the marker has the right to request them if needed.
As the design engineers, your team is tasked to design the support arms, AB and CD, for the lift platform illustrated in Figure 1. Select a carbon steel material and choose a suitable cross section shape with no more than a 4 to 1 ratio of moments of inertia between the two principal directions of the cross section. You may allow the cross section dimensions to vary along the length of the arms to reduce the weight.
The actual structure has four support arms, but the loads shown are for one pair of arms. The loads values are for operating conditions and should have a proper factor of safety applied for human safety.
In developing finite element models, remove the platform and replace it with statically equivalent loads at the joints at B and D. Use truss elements or frame (general beam) elements with low flexural stiffness to the model the arms from B to D, the intermediate connection, and the hydraulic actuator.
a) Develop a Finite Element Model of the lift unit and then calculate the nodal displacements and the stresses in each members (elements) when the platform is loaded as shown. (30 marks);
b) Develop/modify the FE MATLAB programs (given in the class) to calculate the members deformations and stresses. The main program should also be able to display the deformed member comparing the unloaded and loaded conditions (30 marks);
c) Perform similar analysis of the platform in ANSYS WORKBENCH and compare the members deformations and the stresses obtained in (b) and with the ANSYS result in (c) (20 marks), comment on the comparison;
d) Comment on any assumptions made and the design of the lift platform based on your FE analysis. You may propose re-design to enhance the quality of the consulting report or value to your client (10 marks);
e) Present you analysis as professional engineering report (10 marks).
Assoc. Prof. Buyung Kosasih buyung@uow.edu.au
19 March 2017
Figure 1. The lift platform.