Research On Fractal Contact Model And Dynamic Parameters Of Two Cylinders Considering Friction Factor

In the movement of gear mechanism,there are generally characteristics such as uneven force,deformation of the contact surface,friction and wear.Therefore,the solution and analysis of dynamic problems have not been fully understood and mastered.This paper relies on the National Natural Science Foundation of China"Research on gear dynamics behavior influenced by surface morphology based on the friction and lubrication",and carries out frictional contact analysis and dynamic characteristics of gear bearing.In this paper,the gear meshing is simplified as a contact between two cylinders.Based on the M-B model,the influence of friction factors is added,the formula for calculating the critical area of the elasto-plastic deformation of the rough cylindrical surface ?_?c is deduced,and the cylinder surface correction factor is introduced,the correction formula for the contact area distribution of the cylindrical surface n'(?) is obtained.A fractal contact model for the contact capacity of rough cylinders was established and applied to contact bearing analysis.The contact characteristics of the cylinder under different roughness and fractal parameters are studied through software simulation,the trends and laws between the main parameters of the model and the contact bearing capacity are also analyzed,which obtain the most favorable parameters for improving the mechanical properties of the rough cylindrical surface.Based on the existing surface contact stiffness and damping formula,the normal stiffness,tangential stiffness and normal damping fractal model of the rough cylindrical surface are obtained,the calculation method of stiffness and damping with higher calculation accuracy is obtained and applied to the study of dynamic characteristics.The stiffness and damping models were simulated and analyzed by MATLAB to establish the variation law between contact stiffness,damping and load.The effects of parameters(material characteristic parameters,roughness amplitude parameters,etc.)and other factors(meshing method,curvature radius variation)on stiffness and damping in the established model are discussed,which can realize the positive control of rigidity and damping of rough cylindrical surface.Friction and fractal theory are introduced into the study of the dynamic parameters of surface contact,and the influence of friction on the dynamic parameters during the contact between the two cylinders is analyzed in this paper.A new field of gear dynamics research is opened up,and the dynamic theory system is further expanded to be effective,which lays a solid theoretical foundation for effectively improving the quality of gear parts and related products.