Interference Contact and mesh refinement

Hi,

I’ve been able to conduct cylindrical interference study using Calculix/Pardiso solver on relativaly fine mesh but always seems like I’m reaching some limits that I’m struggling to get my head around. If the interference is kept below half of the element width (I’m considering C3D20R/C3D20R or C3D20R/C3D15 with the wedge aligned to the contact normal surface) the calculation goes well and converge towards expected values. However when the mesh is refined and some mid-edge nodes starts to be in interference too, the solver doesn’t even seem to try to resolve the interference and loop through increments until it gives up. The results show some reaction forces at the contact area that would vary depending of the surface contact values but no displacement..

I’ve tried with and w/o incrementation, Nlgeom on/off, swap slave/master without success. So if someone have encountered the same behaviour I’m curious what workaround could do the trick

Thanks in advance !

here some shot of a fine mesh (not working) :

and a ‘coarser’ mesh that works

Could you give a zoom out of that area?.
Is there any other BC on those faces?

There is a lot going on, I deal with half and full revolution cases. The half case have symmetry BC at the symmetry plane. However the largest corrected displacement is not necessarely on one of those nodes when the case is not converging with the fine mesh but rather in a zone with ‘refined mesh’ and elements almost fully in interference. Furthermore I set up cases often reaching more than 1million spring elements..

I will try to create two simple test cases that demonstrate the problem soon

here is the zoomed out picture (the blue part is fixed at the top (not visible) for the interference solving step):

That would be best. To see how it behaves on a small representative segment, maybe even with axial symmetry for simplicity. CalculiX needs good quad/hex mesh for accurate resolution of interference fit but proper node alignment may also be necessary.

Could you try switching surface to surface to node to surface?