点接触弹塑性流体动力润滑研究

Analysis of Plasto-Elastohydrodynamic Lubrication in Point Contacts

建立了点接触混合润滑模型,根据下表面应力分布迭代求解出下表层的塑性应变,将下表面塑性应变等效转化为本征应变,结合半无限体内本征应变对弹性场的应力扰动解法求解残余应力,表面塑性变形根据本征应变采用半解析方法求解.计算结果表明:本混合润滑模型在塑性计算模块、弹塑性流体动力润滑计算均表现出了很好的准确性以及高效性;本模型能够模拟真实机加工粗糙表面下弹塑性混合润滑问题;能够模拟由全膜润滑、混合润滑、边界润滑以及干接触全工况下的润滑情况,当滚动速度逐渐减小时,平均油膜厚度逐渐减小,接触区由全膜润滑转变为混合润滑,最终演变干接触.

The mixed lubrication model in point contacts was developed in the present study, then the plastic strain was obtained by using iteration method according to the distributed subsurface stress. Treating the plastic strain as eigenstrain, the residual stress can be calculated by using the way that disturbed stress caused by eigenstrain in a half space, then the surface plastic deformation was calculated using semi-analytical method according to the plastic strain.Results indicate that the present model were accurate and efficient in the plasticity module and plastoelastohydrodynamic lubrication module. The present model can deal with lubrication with real machined rough surfaces.Besides, the present model can be used to simulate the entire spectrum of lubrication regimes, from full-film and mixed lubrication down to boundary lubrication and dry contact. As the rolling speed decreased, the average film thickness decreased, transition from the full film lubrication to mixed lubrication and finally to dry contact was found.