Three-dimensional contact analysis of layered elastic/plastic solids with rough surfaces

A three-dimensional numerical model is presented to investigate the contact behavior of layered elastic/plastic solids with rough surfaces. The surfac e deformation and pressure distributions are obtained based on a variationa l principle with a fast Fourier transform (FFT)-based scheme. The surface a nd subsurface stresses in the layer and the substrate are determined and a von Mises yield criterion is used to determine onset of yield. The model is applicable for both single-asperity contact and multiple-asperity contact. Three-dimensional layered elastic/plastic solids with rough surfaces are g enerated on the computer with specified standard deviation of surface heigh ts, correlation length, layer thickness, stiffness and hardness ratio of th e layer to the substrate. The contact statistics of layered solids under a designated normal load are predicted, namely, the fractional contact area, contact pressures, surface and subsurface stress, and relative meniscus for ce. These contact statistics are used to investigate friction, stiction, an d wear problems such as debris generation, brittle failure, and delaminatio n. The results yield insight into the effects of the layer, surface roughne ss, and normal load on the tribological performance of layered elastic/plas tic solids. It allows the specification of layer properties to realize elas tic contact and to reduce wear of materials. Optimum layer parameters are i dentified to provide low friction, stiction and wear. (C) 2001 Elsevier Sci ence B.V. All rights reserved.