Learning Forum

[Kshitij Singh]

Hello,

I had performed interference analysis of a simple shaft and hub geometry. Analytical calculations were performed as per mentioned formula. 50% deviation in values of Contact pressure obtained from Analytical calculations & ANSYS Mechanical was observed. I don't understand what is the problem due to which I am facing this issue.

I am attaching images of formula used, geometry, ANSYS model information below for reference.

1. Analytical calculations were performed as per following formula:
   
   
   Input parameters:
   Interference value (δ) = 0.137mm
   d = 151mm, d0 = 159mm, di = 133mm, E0 = 72985MPa (Al alloy), Ei = 200000MPa (structural steel), v0 = 0.3, vi = 0.29
   
   
2. Geometry:
   
   
   
   
3. Contact information:
   
   
   
   Contact initial information:
   
   
4. Contact pressure contour:
   
   
   
   From analytical calculations, contact pressure value obtained for radial interference of 0.137mm was 5.9105MPa. Whereas, in FEA I got contact pressure of 12.3242MPa. I had carried out multiple iterations by changing interference values, but it showed similar deviation between results obtained from both methods.
   
   Thanks in advance.

[Erik Kostson]

Hi

We do have a verification of a similar example in our verification manual.

In ansys help search for VM292:

VM292

VM292
Interference Fit Between Two Cylinders

Hope that helps you.

 

Erik

[Kshitij Singh]

 

I read that example mentioned in verification manual, but there it is solved for case of same material of both cylinders. In my case both parts are having different material (Al alloy & structural steel). 
Here, I am using two different materials and results are having deviation of 50%. I am confused regarding how solver is considering assigned interference (radial or diametrical), as the results are having difference of 50% (factor of 2).

I am attaching my iterative comparison results below in which you can see that:

1. When I assign diametrical interference in both Analytical and FEA analysis, around 50% deviation is observed.

2. In analytical calculation if I assign interference value diametrically, it will match with FEA results if radial interference is added. 

3. I tried solving for same material following the example given in the ANSYS Help, but same problem is observed.

What should I do to solve this problem?