考虑基体变形的结合面连续光滑接触刚度模型

结合面的接触刚度直接影响着机床整机的静、动态力学性能和精度保持性水平。在弹性、弹塑性以及完全塑性接触变形过程中，延续微凸体接触状态变量具有连续且光滑特性的思想，利用Hermite多项式插值函数，建立单个微凸体法向接触刚度模型。考虑到基体变形的影响，在微凸体的3个变形阶段分别引入了基体的弹性接触变形，通过统计学方法，建立了一种考虑基体变形且连续光滑的结合面刚度模型。对比分析了GW、ZMC、KE、Brake模型与该文模型之间的差异，并揭示了表面粗糙度对接触刚度的影响规律。研究表明:考虑基体变形时所获得的接触刚度和接触载荷比忽略基体变形时的要小，且随着表面粗糙度的减小，基体变形的影响快速增加；接触载荷与表面粗糙度是影响结合面接触刚度的2个主要因素，随着载荷的增大或表面粗糙度的减小，接触刚度随之递增。

A CONTINUOUS SMOOTH CONTACT STIFFNESS MODEL FOR JOINT SURFACE CONSIDERING SUBSTRATE DEFORMATION

The contact stiffness of the joint surface directly affects the static and dynamic mechanical properties of the machine tool and the level of accuracy retention. In the process of elastic, elastoplastic and fully plastic contact deformation, based on the idea that asperity contact state variables have continuous and smooth characteristics, a single asperity normal contact stiffness model is established through Hermite polynomial interpolation function. Considering the effect of substrate deformation, the elastic contact substrate deformation is introduced in the three deformation stages of asperity. A continuous smooth joint surface stiffness model considering substrate deformation is established by statistical methods. The differences between GW, ZMC, KE, and Brake models are compared with the proposed model, and the influence of surface roughness on contact stiffness is revealed. The research shows that the contact stiffness and contact load obtained by considering the substrate deformation are smaller than those of ignoring the substrate deformation. The influence of substrate deformation increases rapidly as the surface roughness decreases. In addition, the contact load and surface roughness are the two main factors that affect the contact stiffness of the joint surface. The contact stiffness increases with the increase of the load or the decrease of the surface roughness.