I think you deal with 3d complex geometries and use linear brick elements

Hakim

Dear Moamed,

This is an issue when you use second order elements in combination with node to surface discretization. The matter is explained in the pdf file I have included.

Regards,

Ali

Hi Mohamed,

Contact problems in elasticity are non-trivial to approximate computationally. Algebraically, after the finite element discretisation, they involve solving a constrained optimisation problem. Therefore, relative errors can arise from either the finite element approximation or the numerical optimisation procedure. I suggest that, as you increase the order of the finite elements, try to decrease the mesh-size (of course, this will increase the computational cost of your simulation). If the problem persists, then you are probably in a case where FEM solvers require further improvement/refinement. However, various reliable numerical algorithms are available.

Here is some nice work that you might find relevant in general

Article The Contact Dynamics method: A nonsmooth story

Best wishes,

Angela

Good question.. Please share me the best answer might you trust...

Regards…