Research On Mathematical Model Of Sliding Contact Resistance Based On Rough Surface

With the rapid development of high-speed railway,the problems of pantograph catenary system,which is the power collection device of high-speed railway,are becoming more and more serious.The contact resistance is one of the important indexes that affect the current collection quality of the pantograph catenary system,and the influencing factors are also very complex.The purpose of this paper is to study the contact resistance of sliding electrical contact from the micro contact surface,and to establish the functional relationship between contact resistance and contact load,loop current and sliding speed.Under the condition of high speed and high current,the high-speed relative motion between pantograph slide plate and contact wire will lead to dramatic change of contact surface of pantograph slide plate,which directly causes the change of contact resistance and improves the research difficulty of contact resistance.Therefore,taking the roughness parameter as the intermediate value,the influence of contact pressure,loop current and sliding speed on the rough surface parameters is studied first,and then the functional relationship between contact resistance and contact pressure,loop current and sliding speed is established based on the G-W contact model.Based on the G-W contact model,the relationship between the roughness parameters and the contact resistance between two rough contact surfaces is considered from the deformation and stress of a single micro convex.According to the model,four roughness parameters that affect the contact resistance are deduced,which are:root mean square deviation?R_q?,peak value?R_p?,peak count(R_pc)and curvature radius?r?.The physical model between the contact resistance and the four roughness parameters is obtained,and the mechanism of the influence of the rough surface on the contact resistance is clarified.The results show that the root mean square deviation of rough surface profile decreases with the increase of contact pressure,decreases with the increase of circuit current,increases with the increase of sliding speed,decreases and then tends to be stable with the increase of operation time.The peak value of rough surface decreases with the increase of contact pressure,decreases with the increase of circuit current,increases with the increase of sliding speed,decreases and then tends to be stable with the increase of operation time.Peak count increases with the increase of contact pressure,increases with the increase of loop current,decrease with the increase of sliding speed,decreases and then tends to be stable with the increase of operation time.The radius of curvature of asperity increases with the increase of contact pressure,increases with the increase of loop current,decrease with the increase of sliding speed,increases and then tends to be stable with the increase of operation time.According to the changing trend of contact pressure,loop current,sliding speed and operation time to roughness parameters,power function and exponential function are used to fit,and finally the function relationship is substituted into the model of contact resistance and roughness parameters,and the model of contact resistance and contact pressure,loop current and sliding speed is obtained.The unknown parameters of the model are fitted and solved,and the validity of the model is verified.There are 35 figures,6 tables and 56 references in this paper.