Fractal Model Of Contact Stiffness Of Joint Surfaces Considering Multi-scale Contact State

Joint surfaces exist widely in various mechanical structures or equipments,and their contact characteristics have an important impact on the static and dynamic properties of mechanical structures.When studying the mechanical structure characteristics,the influence of the joint surface must be fully considered.In this paper,fractal modeling of contact stiffness of joint surface is studied.The main work is as follows:(1)Firstly,the characterization of each contact parameter of a single asperity and the relationship between the contact parameter and the scale ordinal number of the asperity in the contact process of the joint surface are introduced,thus a fractal contact model of the joint surface considering the multi-scale contact state is derived.(2)Based on ME model,a fractal model of the normal contact stiffness of the joint surface considering the multi-scale contact state is established,and then the numerical simulation analysis is carried out on the established model.The results show that the normal contact stiffness of the joint surface increases with the increase of the normal contact load,increases with the decrease of the roughness of the joint surface,and increases with the increase of the plasticity index of the material.(3)The fractal model of tangential contact stiffness of the joint surface considering multi-scale contact state is established.The numerical simulation results of the model show that the tangential contact stiffness of the joint surface increases with the increase of normal load of the joint surface,increases with the increase of fractal dimension,decreases with the increase of tangential load of the joint surface and fractal roughness parameters,and increases with the increase of material plasticity index.(4)Comparing and analyzing the model and MB fractal model,the results show that the normal and tangential contact stiffness of the joint surface of the two models have the same change rule,and are verified by experimental examples.The results show that the model built in this paper is closer to theexperimental example results,which shows the correctness and high precision of the model built in this paper.