Modeling the effects of solid thermal expansion and thermal stress on elastohydrodynamic lubrication

Abstract

Temperature has a significant effect on the performance of elastohydrodynamic lubrication (EHL), and this topic has been extensively covered in many studies. These studies are focused on how temperature affects lubrication performance, without considering the effect of temperature on the deformation and the subsurface stress of the contact bodies. However, there will be a significant rise in temperature in the contact area under such conditions as high speeds, heavy loads, and high slide-roll ratios. This will generate significant thermal stress inside the solid, thus inhibiting the elastic deformation of the contact surface and impairing the lubrication performance in the contact area. In such cases, it is essential to consider the effects of solid thermal stress and thermal expansion on thermal elastohydrodynamic lubrication (TEHL). In this paper, a TEHL model that consider solid thermal expansion and thermal stress to solve point contact problems is developed. The effects of solid thermal expansion and thermal stress on pressure, film thickness, temperature, and subsurface stress are investigated. The results show that solid thermal expansion partially inhibits the elastic deformation of the contact surface, resulting in a decrease in film thickness and an increase in pressure. It is also found that solid thermal stress causes the subsurface von Mises stress of the upper contact body to increase and that of the lower contact body to decrease.