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Objectives. Perform finite element analysis of moon buggy suspension using ANSYS WorkbenchEvaluate stress and deformation resulting from applied loadPerform iterations as needed until a satisfactory design is realized. Introduction. Moon buggy originally designed in Spring 2005 by ME 462 design
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1. Moonbuggy Rear Suspension Analysis
ME450: Computer-Aided Engineering Analysis
Department of Mechanical Engineering, IUPUI
Instructor: Dr. Koshrow Nematollahi
May 1, 2006
John Fearncombe
Brandin Ray
Amber Russell
2. Objectives Perform finite element analysis of moon buggy suspension using ANSYS Workbench
Evaluate stress and deformation resulting from applied load
Perform iterations as needed until a satisfactory design is realized
3. Introduction Moon buggy originally designed in Spring 2005 by ME 462 design team
Lower a-arms on original suspension failed
Normal loading conditions were determined to be approximately 200 pounds-force
The initial design was modeled to determine if it could be modified and safely used
4. Theoretical Background Utilized ten-node SOLID92 tetrahedral elements
Ideal for complicated solids with curved boundaries
5. Model Details for Existing Design Originally modeled in Pro/Engineer (IGES), then imported into ANSYS Workbench
Static analysis only
Aluminum alloy construction
200 pounds-force load applied at shock mount
Fixed supports at axes of rotation
Displacement constrained in transverse direction
6. ANSYS Workbench Model of Existing Design
7. Deformed Geometry for Existing Design Maximum Deflection of 2.78×10-3 inches
Maximum deformation occurs near shock absorber mount
8. Principal Stresses for Existing Design Maximum principal stress of 1.791 ksi
Yield stress for 6061 aluminum alloy is 35 ksi
Maximum stresses occur where the part failed
9. Shear Stress for Existing Design Maximum shear stress of 1.421 ksi
Deemed insignificant
Failure due to fatigue in aluminum
10. Model Details for First Iteration Modeled and constrained as before
Aluminum alloy construction
200 pound-force load again applied at shock mount
Modeled as one-piece construction with no welds
11. Results - ANSYS Model of First Iteration
12. Deformed Geometry for First Iteration Maximum Deflection of 5.42×10-3 inches
Occurs below shock absorber mounting bolt
13. Principal Stresses for First Iteration Maximum principal stress of 221.267 psi
Yield stress for 6061 aluminum alloy is 35 ksi
Maximum stresses occur near the shock absorber mounting bolt
14. Shear Stress for First Iteration Maximum shear stress of 20.917 psi
Shear stress concentrated near welds
Quality of welds had been an issue
15. Model Details for Final Iteration Modeled and constrained as before
Aluminum alloy construction with steel reinforcement plates at shock absorber mount
Two points of attachment to wheel hub housing to relieve stress on aluminum members
16. ANSYS Workbench Model of Final Iteration
17. Deformed Geometry for Final Iteration Maximum Deflection of .114×10-3 inches
Located at mid-section of shock absorber bolt
18. Principal Stresses for Final Iteration Maximum principal stress of 1.875 ksi
Yield stress:
6061 aluminum alloy is 35 ksi
4140 steel is 45 ksi
Maximum stresses occur in the steel reinforcing plates
19. Shear Stress for Final Iteration Maximum shear stress of 1.170 ksi
Located in steel reinforcing plates
Achieved objective of localizing stresses within steel elements
20. Impact Statement Through the use of finite element analysis on the rear suspension of the moon buggy the vehicle has become more safe, stable, and easier to maintain.
By optimizing the design before production, we have alleviated costly and potentially dangerous failures.
21. Conclusion - Advantages of Final Iteration Maximum stress is distributed on steel reinforcing plates
Ability to quickly and inexpensively replace the parts most likely to fail
Easier fabrication
No reliance on welds for structural stability
22. Suspension Test
23. Bibliography ME 450 Course Text
ANSYS Website www.ansys.com
Car Suspension and Handling. Bastow, Donald. London : Pentech Press ; Warrendale, Penn. : Society of Automotive Engineers, 1993.
Chassis design : principles and analysis Milliken, William F., 1911-
www.engineersedge.com – Material Properties