ANSYS- Railwheel and Track

Perform a static structural analysis on the Railwheel and Track setup and

Case 1: Multiply the bearing load by 5 times and compare the results with the load of 100000 N (As done in week 2 video). Compare the Total Deformation, Equivalent stress and the life under both the loads

Case 2: Implement a User defined result and calculate the Total Deformation from this result and check if it is the same as that obtained by the inbuilt result by ANSYS for a load of 100000 N.

SOLUTION:

Railwheel and Track setup:

Geometry and Material:

The Railwheel and track geometry are imported into the geometry. The material is setup as Structural Steel.

Contact:

Two contacts are setup:

1. A frictional contact is setup between the wheel and the rail with frictional coefficient of 0.3.
   
   
   
2. A frictionless contact is setup between the axle and the wheel.
   
   
   

Joints:

Three joints are setup:

1. The rail is fixed to the ground using fixed joint.
   
   
   
2. A translational joint is setup between the axle and the ground.
   
   
   
3. A Planar joint is setup between the wheel and the ground.
   
   
   

Mesh:

The assembly is given a mesh size of 50mm. The critical contact portion of the wheel surface is given a face sizing of 35mm.

Analysis Settings:

The analysis is setup for 5 steps as shown below, in which boundary conditions can be specified.

All settings are common for all 5 steps except Auto Time Stepping.
Auto Time Stepping is program controlled for the first step

Auto Time Stepping is manually controlled for the remaining 4 steps as shown below:

Boundary Conditions:

1. A Joint Displacement is given to the translational jointof the axle in steps of 100mm each.
   
   
   
2. A Bearing Load is given to the wheel. The bearing load is the portion of the carriage weight borne by the wheel. This is made parametric input with two values 100kN and 500kN.
   
   
   

Solution:

The desired output variables are selected in the solution as shown above. The File is then solved for.
Some variables are used twice, once for the assembly and then only for the wheel.

Parametric Input(Bearing Load) and Output: Case 1

The Bearing load on the wheel is given two inputs of 100kN and 500kN for the two design points. As Output parameters the maximum stress and the force reaction on the wheel are selected. The obtained solution is as follows:

Stress:

It can be observed that the stress(3.5X) increases but by a lesser factor in comparison to the bearing load(5X).

Force Reaction:

The Force reaction is as expected close to the bearing load itself.

Life:

The life of the wheel seems to have decreased by a factor of 282 while the bearing load increases 5X.

User Defined Total Deformation: Case 2

A User Defined Result is used to obtain Total Deformation using the expression "=USUM".

In comparison, the Total Deformation is shown below with thw exact same result.

Conclusion:

In the rail track and wheel study, the wheel is subjected to fatigue loading. This is on the account of the rotation of the wheel whilst the bearing load direction is in the direction of gravitational pull. The wheel's radial section is subjected to intermitent compression for every rotation with prolonged tension. This has a drastic effect on the life of the wheel, as shown in Case 1.