On the Study of Impact Plasto-Elastohydrodynamic Lubrication of Point Contact Problems Lubricated With Non-Newtonian Lubricant

In this study, the impact of a rigid ball on a substrate with lubricant in between is examined. A linear hardening model for the elastic/plastic substrate deformation is assumed. A power-law model is used to describe the lubricant rheology. Throughout the impact period, variations in the pressure distribution, the film thickness distribution, the velocity of a rigid ball, the impact load, the von Mises stress distribution, and the plastic strain distribution on the substrate are calculated. The special cases of E_T = E in the present impact plasto-elastohydrodynamic lubrication (PEHL) results are in good agreement with previous impact elastohydrodynamic lubrication (EHL) results using a power-law model. The variation of central pressure over time in the PEHL model is flatter and lower compared to that in the EHL model. The significant difference shows that the plastic deformation mechanism should be considered in the simulation. The results indicate that as the flow index (n) increases, the central pressure and central film thickness increase, the pressure spike occurs earlier, and the rigid ball's rebounding velocity and maximum impact load decrease. Moreover, as the tangent modulus of the linear hardening model of the substrate increases, the rigid ball's rebounding velocity and the maximum impact load increase, and the substrate deformation and plastic strain decrease.