I have made a hollow ring as attached. A moving load is applied inside the ring. The moving load can be considered as balls moving inside the outer ring (hollow ring) of a radial roller bearing. In practical applications, the inner ring (not considered here) is attached with a moving shaft while the outer ring is fixed. When I applied fixed boundary condition in COMSOL on the hollow ring shown, it increases the eigenmodes to very large frequency. I suspect the problem is caused by this fixed BC. My question is what boundary condition I should apply on the outer ring to get correct FFT signal ? Except this BC, I have a moving load BC that moves inside the ring. Had anyone studied bearing defect analysis in COMSOL Multiphysics ? Your suggestion and comments are highly appreciated.

Regards,

Muhammad