Analysis of Rail Wheel and Track assembly for varying bearing load conditions

• Objective: 
•             To simulate wheel and  rail track geometry for two different bearing loads and compare the results obtained. To implement user defined result in ANSYS 
• Case Set-up:
1. Provided Rail wheel and track geometry is loaded in Space Claim GUI
2. In modelling tab, contacts between axle and wheel is defined as friction less contact, and contact between wheel and track is defined frictional with friction coefficient of 0.3
3. While defining frictional contacts, faces of wheel and track which are under contact is selected 
4. Fixed joint is defined between track and ground. Translational joint is defined for axle. Planar joint is defined for plane face of wheel
5. Geometry is meshed using a default mesh size of 50 mm. Faces which are under contact are provided with a 35 mm mesh sizing 
6. A five step analysis is set up with minimum time step of 0.001 s and maximum time step of 0.1 s. Direct solver is selected, Large deflections is switched ON and weak springs to be switched OFF.
7. Bearing Load is setup in downward y direction which is defined by components.
8. Displacement of 500 mm is set up in translational joint by adding 100 mm in each step
9. After completing analysis settings, problem is solved using ANSYS solver 
10. Required results such as Total deformation, equivalent stress and life are calculated

Results discussion:

• Case 1 - Bearing Load of 100000 N
• Total Deformation:
• Maximum value: 1001.4 mm
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• Equivalent Stress of Wheel:
  
• Maximum Stress: 169.76 MPa
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• Life of Wheel and track assembly:
• Minimum Life: 46775 cycles 
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• Equivalent stress of Wheel:
• Maximum value: 333.91 MPa
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• Equivalent Stress of Track:
• Maximum value: 351.58 MPa

User defined result for Total deformation:

User defined result is added in solution tab. sqrt( Ux^2 + Uy^2 + Uz^2) is fed as input to determine result. It is concluded that result obtained from user defined result matches with total deformation result provided by ANSYS.

• Conclusion:
• Life of wheel and track assembly is much better in case 1  since maximum stress values are higher in case 2 comparing with case 1.  
  
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• Learning:
  Analysis set up was failing in initial stages due to convergence error. The problem was I have given different settings in some steps. Once the fault was identified, the convergence error was solved. Analysis setting in even a single step will result in convergence error was the learning. Using User defined results was also a major learning.
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