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Analysis with Shrink fit and very small interference

Question asked by Alessandro Tornincasa on Feb 11, 2012
Latest reply on Feb 18, 2012 by Alessandro Tornincasa

Hi,

I would like to determine stiffness of a bearing by performing FEM analysis.

 

Here is the model:

 

1 - model.jpg

 

I'm studying the model on only a slice.

Boundary condtions are:

- one fixed face

- one axial force

- no penetration contact conditions everywhere

- shrink fit contact condition on the faces that are highlighted on the next image

2 - Boundary conditions A.jpg

Bolt connections on two holes:

3 - Boundary conditions B.jpg

 

The interference on the faces where shrink fit contact condition has been put is really low. Here is an esitimate of the diameters:

4 - Interference A.jpg

5 - Interference B.jpg

One radius is 54.9515 mm and the other is 54.950.

The interference is therefore 0.0015 mm .

 

SolidWorks help file states that the shrink fit contact condition is ok to use only if interference is 0,1 % of the bigger diameter.

 

In this case we have:

0.0015/(54.9515*2) = 1.364e-5 = 0.0013 %

 

Infact, if you look at the deformed shape (in attach is the video) it looks like the interferering component is applying a too high force to prevent interference.

 

What should be done in this case:

- Should you just remove interference and use a no penetration contact condition ?

- Is this "high interference force" due to the fact that the mesh is too coarse ?

- Should I use a very fine mesh (maybe as big as the intereference (0,0015 mm) ?

 

I'm unsure about what I should do because there are very smal displacements and maybe even the preload due to the shrink fit contact could play some role.

 

Thanks,

 

Alex

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