Abstract: The contact mechanism of bolted-joint interface in elastic-plastic deformation regime is difficult to determine. Acrooding to the contact mechanics and the assumption that the transition from elastic to fully plastic deformation of a contacting asperity is continuous and smooth, the new polynomial function is constructed to describe the relationship between contact deformation and real contact area in elastic-plastic contact regime. The real area of contact, contact load and contact stiffness model are developed based on statistical method. Theoretical calcutaion results show that contact load, real contact area and contact stiffness increases as the mean surface separation decrease. The real contact area and contact stiffness increases with the increases of the contact load, especially, the value of contact stiffness and real contact area approached to ideal contact stiffness and nominal contact area when the contact load increases to a certain extent, respectively. The real contact area increases as plasticity indices increases, and mean surface separation and contact stiffness decrease in the elastic and elastoplastic deformation regime. The mean surface separation and contact stiffness increases as plasticity indices increases, and real contact area decreases in the fully plastic deformation regime.

Key words: asperity, bolted-joint interface, contact mechanics, elastic-plastic contact model, statistical method