Modeling multi-physics electrical contact on rough surfaces considering elastic-plastic deformation

A multi-physics electrical contact model is proposed to study electrical, thermal, and mechanical behaviors on rough surfaces, in which the elastic and plastic deformation of asperities is considered. The rough surface is generated by a two-dimensional Weierstrass-Mandelbrot (WM) function. The contact spot morphology is obtained by a boundary element method. The deformation state of each contact spot is determined by the comparison between the critical compression displacement and the actual displacements obtained from the BEM results and geometrical analysis. The multi-asperity electrical contact problem is then treated as a group of single-asperity electrical contact problems on contact spots. The contact force, real contact area, electric current, electrical contact resistance, and maximum temperature rise of each asperity are predicted by using the singleasperity electrical contact model proposed in our previous study. The electrical contact behaviors on rough surfaces are determined by summarizing the contributions from all contact asperities. Moreover, the electrical contact behaviors on rough surfaces are simulated using finite element analysis to validate the proposed model. The comparison shows an excellent agreement between the theoretical solutions and the FEA results. The applicable range of the theoretical model is also studied. The effect of the random phase in the WM function on the electrical contact behavior is evaluated using the developed model.