边界润滑下滑动接触表面破坏行为的数值分析

Numerical Analyses of Breakage Behavior of Rolling Contact Surface under Boundary Lubrication

针对边界润滑条件,本文用有限元方法分析了当滚动接触处于准静态情况下,接触表面覆盖有水边界膜而且接触区内存在微观突起和微观裂纹的接触状态,阐明了液体对表面微观裂纹的影响。分析结果表明液体的存在改变了接触区的受力状态,表面裂纹造成接触区应力分布的不连续;有水存在时,最高接触压力降低并且分布均匀,但造成应力强度因子K_1增大,促进裂纹的扩展。

As a real surface is rough and with cracks, liquid is considered to be closed in surface troughs of corrugation when the breakage of rolling contact surface is analyszed. Metal pairs are adhesive together due to asperity peaks penetrating the liquid film. The contact state with water film under boundary lubrication on rolling contact surfaces is analyzed by finite element method in this paper. Stress distribution was calculated from the models with asperity. When water exits on rough surface, it can reduce the stresses intensity. Mode I stress intensity factor at the crack tip was investigated. K\ has an obvious rise when water seeped into crack. These micro-cracks may wear off inevitably or grow into shells. Water is essential for fatigue micro-cracks to develop into defects.