Predictions of the average surface separation and stiffness between contacting elastic and elastic-plastic sinusoidal surfaces

The behavior of regular wavy surfaces in contact is important for the study of rough surface contact, and therefore has applications to the prediction of friction, wear, surface fatigue, and electrical and thermal contact resistance. This work characterizes the average surface separation between a sinusoidal surface and a flat rigid surface as a function of the average contact pressure or load using the finite element method (FEM). The FEM results also agree well with the limiting spherical based solutions at low contact pressures and the other asymptotic solution at high contact pressures. Empirical fits are provided that can approximately predict the average surface separation for both elastic and elastic-plastic sinusoidal contacts over a wide range of material properties. Contact stiffness can also be predicted from surface separation results.