结合面静态接触参数的统计模型研究

Statistical model for static contact parameters of joint surfaces

基于对粗糙表面形貌统计分析的基础上,综合考虑微凸体的完全弹性、弹-塑性和完全塑性三种变形机制,建立了结合面的接触面积、接触载荷及接触刚度的统计模型。该模型揭示了结合面接触参数与材料性能参数及粗糙表面形貌参数之间复杂的非线性关系。在不同的微凸体高度随机分布及塑性指数条件下,对接触参数进行预估和对比研究。结果表明,修正的指数分布对高斯分布有着较好的近似,而简单的指数分布与高斯分布之间的误差较大,且相差1至3个数量级;接触表面间距减小时,接触参数值均呈现增大的趋势;塑性指数增大时,接触载荷和接触刚度都随之增大,而接触面积的变化较小。

A statistical model for static contact parameters of joint surfaces was established.The model was developed based on statistical analysis of surfaces topography,and the assumption that the transitions from fully elastic deformation,through elastoplastic one,to fully plastic one of an asperity be continuous.The nonlinear relationships between contact parameters and their influencing factors were simulated numerically under different random distributions of the asperity height and plasticity indices.The results indicated that the modified exponential distribution is a good approximation of Gaussian distribution; on the other hand,the estimations for contact parameters using the simple exponential distribution are 1 to 3 orders of magnitude larger than that of Gaussian distribution; all the contact parameters will increase when the mean separation between the two surfaces decreases; in addition,the contact load and the contact stiffness increase with the plasticity index,but the changes in contact area are not significant.