Loading-unloading normal stiffness model for power-law hardening surfaces considering actual surface topography

Contact surfaces widely exist in the engineering applications and their contact behaviors strongly affect the mechanical performance. The normal contact stiffness, as an important contact parameter, is studied during loading and unloading process. The normal stiffness of single asperity contact is calculated based on the contact between a power-law hardening hemisphere and a rigid flat under full stick condition and the shoulder-shoulder contact form. The actual surface topography is considered efficiently to build the stiffness model of contact surfaces. The stiffness predicted by the proposed model is verified by the experiments.