The stiffness of mechanically fastened joints influences static and dynamic characteristics of machine tools. The conventional contact stiffness model considers only the deformation of roughness asperities based on uncertain topographic parameters. This study presents a holistic contact stiffness model considering the subsurface deformation and avoiding assumptions of topographic characteristics, which tend to introduce uncertainty. Subsurface deformation was also investigated via stress distribution measurements and finite element simulations. Using the proposed model, the stiffness of jointed parts was estimated with an error <15%. Moreover, the subsurface deformation's influence on contact surface design was discussed.

机械紧固接头的刚度影响机床的静态和动态特性。传统的接触刚度模型只考虑了基于不确定地形参数的粗糙凹凸不平的变形。本研究提出了一种整体接触刚度模型，该模型考虑了地下变形并避免了往往会引入不确定性的地形特征假设。还通过应力分布测量和有限元模拟研究了地下变形。使用所提出的模型，连接部件的刚度估计误差<15%。此外，还讨论了地下变形对接触面设计的影响。