A modified normal contact stiffness model considering effect of surface topography

The contact stiffness of joint surfaces is an important factor influencing the static and dynamic characteristics of the mechanical equipment. In the present research, a modified normal contact stiffness model of two rough surfaces is proposed. First, the stiffness model of a single asperity contact pair is obtained based on shoulder-shoulder contact in conjunction with the elastic-plastic contact model proposed by Jackson and Green. Second, the topographies of contact surfaces are analyzed, and the locations of asperities and the statistical distributions of asperity heights and radii are acquired experimentally. The asperities are then generated using Monte Carlo method with the information to simulate the real contact. Finally, the asperities contact state is determined and if the contact occurs, the stiffness of the single asperity pair is calculated and summed as the total normal stiffness of two contact surfaces. The proposed stiffness model is validated by experiments with the errors less than 10%.