基于微凸体连续变形理论的结合面切向刚度模型  

Tangential stiffness model for joint surface based on asperity continuous deformation theory

作　　者：王世军[1] 李志涛 韩子锐 赵金娟 李鹏阳[1] WANG Shijun;LI Zhitao;HAN Zirui;ZHAO Jinjuan;LI Pengyang(School of Mechanical and Precision Instrument Engineering,Xi’an University of Technology,Xi’an 710048,China;School of Printing,Packaging Engineering and Digital Media Technology,Xi’an University of Technology,Xi’an 710048,China)

机构地区：[1]西安理工大学机械与精密仪器工程学院,陕西西安710048 [2]西安理工大学印刷包装与数字媒体学院,陕西西安710048

出　　处：《西安理工大学学报》2019年第4期401-410,共10页Journal of Xi'an University of Technology

基　　金：国家自然科学基金资助项目(51675422);陕西省科技厅科技统筹创新工程重点实验室资助项目(2014SZS10-P05)

摘　　要：提出了一种包含微凸体接触过程中弹塑性过渡阶段弹性的粗糙表面切向接触刚度模型。现有粗糙表面切向接触刚度模型中只考虑微凸体完全弹性接触阶段的弹性,未考虑弹塑性过渡阶段弹性。根据微凸体变形过程中应满足的连续性条件,微凸体变形过程可以按如下划分:完全弹性阶段、弹塑性过渡阶段(包含三个不同阶段)以及完全塑性阶段,依据分形理论和Hertz接触理论,建立了计入微凸体弹塑性过渡阶段弹性的结合面切向接触刚度模型。分析与试验结果表明:考虑微凸体的弹塑性过渡阶段的切向接触刚度相比与不考虑弹塑性过渡阶段更加的符合实际接触情况。新模型的切向接触刚度随着法向载荷和较软材料的屈服强度与两材料的复合弹性模量的比值的增大而增大,还由于分形粗糙度与切向载荷的增大,该切向接触刚度会减小,并且伴随着分形维数的增大,切向接触刚度先增大后减小,即接触刚度存在一个峰值。此外,当较软材料的屈服强度与两材料的复合弹性模量的比值增大时,刚度峰值所对应的分形维数在减小。A tangential contact stiffness model of rough surface is proposed,which includes the elasticity of elastic-plastic transition stage in the asperity contact process.The existing tangential contact stiffness models of rough surface only consider the elasticity of the fully elastic contact stage of asperity,but do not consider the elasticity of elastic-plastic transition stage.According to the continuity conditions that should be satisfied during the deformation process of asperity,the deformation process of asperity is divided into complete elastic stage,elastic-plastic transition stage including three different stages,and complete plastic stage.So based on the fractal theory and Hertz contact theory,a tangential contact stiffness model of the joint is established,considering the elasticity of the elastic-plastic transition stage of asperity.The results of investigation and the experience show that compared with the model not considering the elastic-plastic transition stage of asperity,the tangential contact stiffness of the model considering the elastic-plastic transition stage of asperity well matches the realistic contact situation.The tangential contact stiffness of the new model increases with the normal load and the ratio of the yield strength of the softer material to the equivalent elastic modulus of two materials,which also decreases with the fractal roughness and the tangential load.And as the fractal dimension increases,the tangential contact stiffness increases first and then decreases,which means that a peak exists in the change of the contact stiffness.Furthermore,when the ratio of the yield strength of the softer material to the composite elastic modulus of the two materials increases,it is found that the fractal dimension at the peak of the stiffness will decrease.

关 键 词：结合面 分形理论 弹塑性 接触 切向刚度 

分 类 号：TH113.1[机械工程—机械设计及理论]