Abstract:To explore the effects of different acceleration and deceleration forms on the elastohydrodynamic lubrication(EHL) mechanism of UHMWPE bearings during the acceleration and deceleration process,the EHL model of seawaterlubricated UHMWPE bearings was established.Based on the Reynolds equation considering timedependent effect,the lubrication of UHMWPE bearings under different acceleration and deceleration conditions was numerically simulated.The results show that during the accelerating process,the cosine acceleration form is the most beneficial for lubrication in which the film thickness is least affected by the squeezing effect at the initial stage of acceleration,and the film thickness is not too thin or even broken.At the same time,the pressure is the smallest,the film thickness is the largest,the friction coefficient is the smallest,the transition is the smoothest when entering the steady state,and the shock on the shaft and the bearing is the smallest.During the decelerating process,braking in the form of sinusoidal acceleration is most beneficial for lubrication.Since the speed change process is extremely short,the squeezing effect caused by the timedependent cannot be ignored.By comparing the film thickness at different times during the startstop phase,the squeeze effect makes the pressure,film thickness and friction coefficient change and decay for a long time after the end of the speed change.The timedependent of the braking phase is more obvious than the startup phase.The greater the acceleration,the more obvious the dynamic effect,the sooner the second fluctuation of pressure occurs in the startup process and the first fluctuation occurs in the braking process.