Week 2 Railwheel and Track
The objective of this assignment is to analyze the total deformation, equivalent stress and life of this geometry under two specific loading conditions. Further, user defined results are attained and evaluated for total deformation with its corresponding expression. Two specific loading conditions are:
- Bearing load with, 100000 N
- Bearing load with, 5x100000 N
Set up
Geometry
Material:
Connections made within the geometry parts:
A frictional Contact is made to wheel and rail, and frictionless contact is made between wheel and shaft.
Fixed joints are made at the rail to constrain all DOF, Translational joints are made along the rail in x-axis direction, and Planar joint are made at the wheel face as shown in the diagram.
Mesh: element size of 35 mm is given for both loading conditions. Face Sizing, an element size of 35 mm, is also provided at the contact regions of wheel and rail for higher accuracy.
A bearing load of, 100000 N is applied (case 1) & (50000 N for case 2)and a displacement joint of 500 mm applied with 5 steps. Time steps applied is 1e-3. Max time step is 0.1.
CASE 1
i). Result for the load of, 100000 N
Total deformation: (Max - 999.14 mm)
Equivalent stress: (max - 148.44MPa)
Equivalent stress on wheels: (Max - 129.29MPa)
Fatigue life
ii) Result for the load of, 500000 N
Total deformation: (Max - 1001.5 mm)
Equivalent Stress (Max - 554.42MPa)
Equivalent stress on wheels (Max - 458.46MPa)
Fatigue Life:
| Total deformation | Equivalent Stress | Equivalent stress on wheels |
Fatigue Life (Cycles) |
|
| Load - 1e5N (Max values) | 999.14 mm | 148.44MPa | 129.29MPa |
1e6 (Max) 4.431e5 (Min) |
| Load - 5e5N (Max values) | 1001.5 mm | 554.42MPa | 458.46MPa |
1e6 (Max) 1102.9 (Min) |
The total deformation remained unchanged against changing loading condition (~ 1000 mm). Equivalent Stress on track is showing a large deviation from initial loading as the load increased to 5e5N, I.e, 5 times the first case. There is a similar change in the equivalent stress in wheels, but slightly lower values than the first case (129.29 - 458.46 MPa). Evidently, the stress increases with increase in load. Max equivalent stress is observed where both the surface comes in contact.
Fatigue life results shows vital observation about the failure of the geometry. Min fatigue life of load 1e5N has a value 4.431e5 cycles (Min) when the load is increased to 5e5N the life value drastically drops to 1102.9 cycles. Material has a high life at load 1e5N.
Case 2
User defined result details:
Expression: sqrt(Ux^2+Uy^2+Uz^2)
where X, Y, Z are the directional axis.
The total deformation result for both the loading cases are same for user defined and inbuilt result in Ansys.
Animations of stresses:
