Abstract:In order to accurately calculate the normal and tangential contact stiffness of rough surface between high speed wheel/rail,a threedimensional numerical model of high speed wheel/rail surface roughness was established based on WM function fractal theory.The wheel/rail normal and tangential contact stiffness theory was analyzed,and the finite element method was used to discrete the wheel/rail contact surface for establishing the simplified contact finite element model of the wheel rail rough surface.The penalty function of face to face contact algorithm was used to the wheel/rail contact,and the displacement load was applied to calculate wheel/rail normal and tangential contact stiffness.The results show that the normal and tangential contact stiffness can be calculated more accurately when considering the surface roughness of wheel/rail under contact load.The normal contact stiffness of wheel/rail is greatly affected by normal load,and which is increased with the increasing of normal load,while the friction coefficient has little effect on the normal contact stiffness.The tangential contact stiffness is increased with the increasing of normal load and friction coefficient,and decreased with the increasing of shear load.