Theoretical Model of Tangential Contact Stiffness and Damping of Solid-Liquid Interface in Macroscopic Relative Motion

The macroscopic relative motion solid-liquid interface widely exists in the contact motion pairs of machine tools and other mechanical equipment. In order to accurately obtain the tangential contact stiffness and damping parameters, the Savkoor asperity adhesion-sliding friction contact model is used to analyze the contact area and the corresponding tangential force changes of a single pair of solid contact asperity in the four typical phases of contact growth, contact stagnation, crack adhesion and crack propagation. According to the hypothesis of Gaussian distribution of asperity on rough surface, the contact model of single-pair asperities is extended to the whole joint. The tangential contact stiffness and damping models of solid-solid interface in macroscopic relative motion are obtained. For the fluid contact part, the oil film pressure distribution and film thickness are obtained by solving part of the film Reynold’s equation, and then the fluid tangential stiffness and damping model is established. The tangential contact stiffness and damping of the whole solid-liquid interface are obtained by analyzing the stiffness and damping of solid and fluid parts, and the effects of normal load and moving velocity on tangential contact stiffness and damping are obtained by simulation. The results show that the tangential contact stiffness and damping of solid-liquid interface increase with the increase of normal contact load and decrease with the increase of moving velocity.