Finite element simulation of inelastic contact for arbitrarily shaped rough bodies

Abstract

Accounting for surface roughness in contact simulation can significantly change the calculated values of contact stresses for many objects. This can be important for high-precision mechanisms where displacements of tens of micrometers are required, such as a machining attachment used to clamp machine elements during processing on high precision machine tools. In this case, even a small deformation changing the shape of asperities can be sufficient to influence the operation of the mechanism. For problems with extensive contact areas and relatively low nominal contact pressures, accounting for surface roughness can change the distribution of the contact stresses and the contact area. Therefore, a contact simulation should be run with minimum set of assumptions. A universal approach to account for surface roughness in the contact of arbitrarily shaped bodies using the finite element method is described. A contact between bodies with nominally flat rough surfaces is considered in order to obtain diagrams of normal and tangential contact stiffness. An elastic-plastic pattern of material deformation is determined using yield theory. The distribution of the contact area during load growth is discussed. The application of contact stiffness diagrams in contact simulation for rough is described, and some numerical results are given.