Fractal prediction model and simulation of contact stiffness considering friction factors between joint surfaces

In order to accurately consider the influence of friction on the joint surfaces, the fractal prediction model of the contact stiffness of joint surfaces is established based on tribology theory and fractal contact theory. Then the kinetic model of joint surfaces is improved to a certain extent. The influence of actual contact area, contact force and friction coefficient on the contact stiffness is revealed with the research of numerical simulation. Simulation results indicate that normal contact stiffness of joint surfaces increased with the increase of actual contact area, increased with the increase of contact force. And when the friction coefficient is less than 0.3, the normal contact stiffness appears linear attenuation with the increase of the friction coefficient. And when the friction coefficient is larger than 0.3, normal contact stiffness appears exponential attenuation with the increase of the friction coefficient. Tangential stiffness appears to be the similar rules with different parameters.