An improved analytical model for normal elastic-plastic contact of rough surfaces

An improved analytical model for elastic-plastic contact in the normal direction of rough surfaces is developed. The problem can be considered in three separated phases: the elastic phase, the mixed elastic-plastic phase, and the fully plastic phase. In the elastic phase, Hertz's elastic contact formulations are used; in the fully plastic phase, classic fully plastic contact assumptions are used; and for the mixed elastic-plastic phase, the contact behavior is approximated by an elliptic curve interpolation. The contact model of the rough surfaces is then formulated using probability and statistics theory. The developed model is compared with other classical models. It is shown that the proposed model can describe the monotonic, smooth and continuous changing relationship of asperity's contact state variables with the normal contact displacement. The proposed model can model the contact behavior of the rough surface and agrees well with the finite-element based rough surface contact model.