Surface Roughness Characteristics And Contact Resistance Mathematical Model Of Sliding Electrical Contact

The high-speed railway train obtains electric energy through the pantograph catenary system.The good current collection between the pantograph and the catenary is the premise of the safe and stable operation of the train,and the contact resistance is the most important factor affecting the current collection quality.In the actual operation of the train,the high-speed relative motion between the pantograph and the catenary will lead to the drastic change of the contact surface,and then result in the change of the contact resistance.In order to study the change mechanism of contact resistance.The change of contact resistance is closely related to the contact state of the contact surface of the pantograph friction pair,and the contact surface topography directly affects the contact state of the contact surface.So,this paper takes the roughness parameter of contact surface as the intermediate quantity.Firstly,the change rule of roughness parameter under different experimental conditions and the relationship between contact resistance and roughness parameter are studied.Then,the Greenwood-Williamson model is modified,based on which,the mathematical model of contact resistance with contact pressure,sliding speed and contact current is established.Based on the modified G-W model suitable for elastic-plastic contact surfaces,this paper derives the relationship between contact resistance and arithmetic mean of rough surface profile R_a,peak count R_pc,and curvature radius of asperityβ,and clarifies the change mechanism of contact resistance from a microscopic point of view.The effects of contact pressure,sliding speed and contact current on the three roughness parameters are studied.The results show that the larger the contact pressure is,the smaller the arithmetic mean of rough surface profile is,the larger the peak count is,and the larger the curvature radius of asperity is;the higher the sliding speed is,the larger the arithmetic mean of rough surface profile is,the smaller the peak count is,and the smaller the curvature radius of asperity is;the larger the contact current is,the smaller the arithmetic mean of rough surface profile is,the larger the peak count is,and the larger the curvature radius of asperity is.The relationship between contact resistance and the arithmetic mean of profile R_aunder different contact pressure,sliding speed and contact current is studied.The results show that with the increase of contact pressure,sliding speed and contact current,the contact resistance will decrease,increase and decrease respectively.The change of contact resistance is positively related to the change of the arithmetic mean of profile.Based on the changing trend of three roughness parameters with macro quantity,power function and exponential function are used to fit them respectively,and the functional relationship between roughness parameters and macro quantity is obtained,which is finally substituted into the model of contact resistance and roughness parameters to obtain the mathematical model of contact resistance with respect to the macro quantity,and the model parameters are obtained by nonlinear fitting 1st Opt,and the reliability of the model is verified.There are 39 figures,6 tables and 57 references in this paper.