Meshing for Contact Analysis

Once the source and destination boundaries are chosen, you should mesh the destination finer than the source. Do not make the destination mesh just barely finer than the source because this can cause nonphysical oscillations in the contact pressure. Make the element size on the destination at least two times finer than on the source. The reason is that the algorithm is asymmetric; the points on the destination side connects to the source side, and not vice versa. So with a coarse mesh on the destination side, a large portion of an element (or even a whole element) on the source side could be without connection to the destination.

It is always important that the geometry is well resolved, so that a curved contact boundary actually is seen as curved rather than “faceted”. The density of the mesh often needs to be finer than what would be needed to resolve stresses on a similar boundary without the contact conditions. If the normal to the contact boundary changes much from one element to the next, there is a risk that the contact analysis does not converge.

If the source boundary is rigid, there are no requirements on the mesh size of the destination boundary. In this case, you may use a significantly finer mesh on the source boundary than on the destination boundary. This is sometimes necessary in order to resolve the geometry well. On the other hand, if you have a flat rigid boundary, you only need to mesh it with a single element.