Research On Modeling Of Tangential Contact Stiffness And Contact Damping Of Joint Surfaces Considering Asperity Interactions

The contact stiffness and contact damping of joint surface have a dorect influence on the dynamic characteristics of machine tools,and its modeling problem has always been a research hot topic in the academic world.In view of the fact that the research work on the tangential contact stiffness and tangential contact damping of the joint surface does not consider the influence of the asperity interactions,this paper mainly carried out the following research work.1)On the basis of summarizing and analyzing the current situation and shortcomings of the research on the contact stiffness and contact damping of the joint surfaces,the main research contact of the paper is clarified,that is,the modeling research on the tangential contact stiffness and tangential contact damping of the joint surfaces considering the asperity interaction.2)Based on the displacement of the average plane of the asperities on joint surfaces under loading,that is the asperity interaction,the relationship between the normal contact load,tangential contact stiffness and the contact area of a single asperity are derived.Then the relationship between the normal contact load and the actual area of joint surfaces considering the asperity interaction was deduced based on MB contact fractal theory,and the fractal model of tangential contact stiffness of joint surfaces considering the asperity interaction is set up.The fractal model is simulated,analyzed,compared and verified with experiment example.3)Based on the fractal model of the tangential contact stiffness of joint surfaces considering the asperity interaction,the tangential contact damping energy dissipation of an asperity derived,and the tangential contact damping energy consumption of surfaces is derived.Based on the hysteretic energy dissipation mechanism of tangentail contact damping of joint surfaces the dissipation factor of the tangential contact damping of joint surfaces are obtained,and then the fractal model of tangential contact damping of joint surfaces is proposed considering asperity interaction.The influences of the fractal dimension,fractal characteristic length scale parameters,the normal contact load and material plasticity index and other factors of joint surfaces have influence on tangential contact damping have been researched,and the proposed model is verified by experimental examples.