LAUSR

A loading–unloading elastic–plastic model of contact between three dimensional fractal rough surfaces has been presented in this paper. During loading process, the mechanical properties of a single asperity follow Hertzian theory. During unloading process, the load-area relationships of a single asperity are obtained by EK model. The truncation size distribution functions for different levels of asperities are deduced. And total true contact area and total contact load are obtained during a loading–unloading process. The results show as the rough surface is in elastic deformation, the load-area relationships during loading and unloading process are identical. As the rough surface is in inelastic deformation, the total true contact area during unloading process is greater than that during loading process. An experiment is designed to verify the validity of the present model.