Stick-slip friction modeling of structural joint interface considering rough contact

A novel joint interface nonlinear model considering rough contact is presented. The model is based on Kragelsky-Demkin rough contact mechanics and Iwan hysteretic model. First, the relationship of interface restoration force distribution with the surface roughness parameters is established, and the probability distribution density of local critical slip force is derived from the Kragelsky-Demkin rough contact mechanics. Then, adopting Iwan continuous hysteretic model, the relationship between interface tangential loading and relative displacement, as well as the relationship between energy dissipation per unit period and amplitude of tangential oscillating loading, is built. Finally, the effects of roughness parameters on the interface tangential stiffness and energy dissipation are investigated. It is shown that the proposed model can directly express the relationship between interface macro-mechanics and surface roughness; the tangential restoring force is a nonlinear function of interface relative displacement, and the tangential contact stiffness decreases with the increase of relative displacement; the larger the surface roughness, the higher the tangential contact stiffness and the smaller the frictional energy dissipation; the energy dissipation per unit period is a power function of the amplitude of tangential loading.