The Effect of Surface Smoothing and Mesh Density of Real Surfaces in Contact

Abstract

In our previous work (Kwon 2009), we examined the effect of finite element mesh density on real measured surfaces in contact. The results showed that more than one element per asperity provides no real benefit relative to solution costs. However, the techniques used to generate the surfaces in the finite element model resulted in sharp peaks at the apex of each asperity. When these asperities touch other surfaces in finite element models, the two surfaces initially experience point contact which can be expanded to 2D or 3D contact under higher loads. In rare cases, this can create a numerical singularity and prevent the model from solving. It was hypothesized that this phenomenon could also be responsible for the observed hyper-sensitivity of the maximum contact pressure during mesh refinement. However, these sharp peaks are not a necessity. The surface can be smoothed using splines or other curve fitting technology to avoid the creation of sharp surface peaks. This work examines the effect of surface smoothing and mesh density for finite element modeling using real measured surfaces in contact with an ideal, non-deformable target surface. Since surface smoothing and mesh density are coupled, the effects of both are considered together. The results of smoothed and non-smoothed surfaces at a variety of mesh densities and applied loads are presented.