- May 15, 2020
Page 1 of 5 Finite Element Analysis – Assignment 2 MIET1084 – 2019 Assignment 2 Total Marks – 15 (15% of course mark) Due Date – Friday, 20th September 2019 Background You have been tasked with the structural design of a vehicle moment of inertia swing rig. The swing rig is designed to provide a platform to be able to determine the moment of inertia of a vehicle in various orientation. The vehicle is placed on the platform, which is suspended on a frame, and then subsequently swung back-and-forth. The period of oscillation of the swinging frame is measured, and subsequently utilised to determine the moment of inertia of the vehicle parallel to the axis of the swing’s rotation. The important design parameters of the swing rig are its mass and stiffness. In addition to improving the maintainability and serviceability of the system, a low mass reduces the error in the measurement of the vehicle’s inertia (the inertia of the rig can be subtracted from the calculation, a larger mass increases the uncertainty of the measurement). A stiffer swing rig will have a larger percentage of its kinetic energy in the swinging mode, thereby increasing the accuracy of the measurement. You will be provided overall dimensions of the swing rig to be designed, a list of mandatory structures, the details of the proof load case and a list of beam cross sections that may be utilised in the design. You will be required to design a rig that, at the proof load, has a yield stress factor of safety greater than 10 and a static deflection less than 2.00 mm. The rig must have a mass less than 180 kg. Figure 1. Example schematic of a vehicle motion of inertia swing rig. Page 2 of 5 Finite Element Analysis – Assignment 2 Task You are to utilise Abaqus to construct the geometry of the rig shown in Figure A1, including both the base and the swing arms. Please note that the structure shown in Figure A2 represents the minimum structure permissible; more structural members may be added to the frame as required. It is highly recommended that a base analysis is conducted utilising smaller section sizes available as per Table A2, the base geometry shown in Figure A1 and the load case presented in Table A1. The beam cross section profile provided in Table A2 must be adhered to. Once the initial design has been analysed, you are to adjust the design, such that the design meets the mass, safety factor and displacement requirements provided above. All tube members must be manufactured from AISI 1010 steel, with material properties found in Table A3. No tube members of the final chassis may intersect the section shown as the ‘Exclusion Zone’ in Figure A3. Note that the coordinates of the frame shown in Figure A2 should be adhered to in the analysis. Please note that the swing arms may be either pinned jointed or fully fixed to the base frame, and that the they may be represented as either truss or beam elements, as per your designed of the rig. Submission You are to complete your report as per the template available on the Canvas site. Your report and work will be assessed as per the report marking scheme in Table 1. Additionally, you are to submit the .cae, and .odb files of your final analysis. These files will be used as clarification of work and results during assessment and grading. Report Layout Table 1 Submission Description Abstract A short statement on the problem addressed, the work undertaken and quantification of the final outcomes. Introduction Provide a brief overview of the problem. Nominate the objectives and aims of the work, which will be undertaken and addressed in the subsequent sections Finite Element Model The details of your finite element model should be provided in this section. Appropriate engineering reasoning should be given for the analysis and modelling techniques. Topics covered should include; geometry, element types, meshing strategies, material properties, boundary conditions, loads and outputs. Design Development The outcomes of your initial FE analysis should be reviewed relative to the system specifications. Potential design improvements should be made to the system and subsequently analysed using the finite element method. Weighting will be given to both your capacity to efficiently and effectively interpret the outputs of the simulations and the methods taken to improve the design. Results Finalise the outcomes of your analysis process. Make appropriate use of figures, tables and graphs. Ensure that all graphical work is meaningful in context and specific. Discussion Describe efforts made to ensure your analysis is reliable and verified. Discuss how validation of the analysis could be achieved. Conclusion Summarise and formulate the outcomes of your work. Ensure that this section addresses the fundamental problem being studied. Communicate any potential improvements that could be made beyond the scope of the report. Page 3 of 5 Finite Element Analysis – Assignment 2 Appendix Table A1. Load cases to be examined Load Name Loads Applied Application Point Displacement Boundary Conditions Full Vehicle Load Case Fy = -5000 N Equally distributed across the blue patches as per Figure 2 and Figure A1 Fixed translation in all directions and fixed rotation in x-axis Fixed Nodes, shown in Figure A2. Gravity Entire System Table A2. Available Cross Sections Tube Members Source Rectangular Hollow Section https://www.orrconsteel.com.au/products/tube-pipe/structural/rectangular-hollow-section Square Hollow Section https://www.orrconsteel.com.au/products/tube-pipe/structural/square-hollow-section Channel Section https://www.orrconsteel.com.au/products/hot-rolled-structural-steel/channel I-Beams https://www.orrconsteel.com.au/products/hot-rolled-structural-steel/beam Table A3. AISI 1010 steel material properties Young’s Modulus (GPa) Yield Strength (MPa) Ultimate Strength (MPa) Density (kg/m3) 200 305 365 7872 Page 4 of 5 Finite Element Analysis – Assignment 2 Figure A1. Overall schematic of the base frame. Note the dotted lines represent the centreline of the beam Page 5 of 5 Finite Element Analysis – Assignment 2 Figure A2. Isometric view of the swing rig. Note the Fixed Nodes and the load application zone shown in blue. The swing arms (shown in grey dotted lines) may be either fully fixed to the base frame, or they may be pin jointed. Figure A3. Side view of the swing rig. Note the height of the swing rig and the exclusion zone shown in green.