Simulation Study On Microscopic Friction And Wear Of Brake Interface Of High-power Disc Brake

The brake disc surface of high-power disc brakes is a rough surface composed of countless irregular micro convex bodies.Under high-speed and heavy-duty braking conditions,the micro convex bodies scratch the surface of the brake pad,causing abrasive wear.The micro convex bodies in contact with the brake pad on the brake disc surface are subjected to a large load,resulting in wear and affecting braking efficiency.Therefore,studying the microscopic process of friction contact at the braking interface is of great significance for reducing the wear of the braking interface and improving the working performance of the braking friction pair.This thesis focuses on the friction and wear of the braking interface of high-power disc brakes,and studies the micro friction process and wear law of the braking interface.The main research content is as follows:(1)By using the discrete element theory and the basic contact model of particles,a particle contact model of the brake pad is established,and the wear failure criteria of the brake pad were determined.The stress-strain curve of the brake pad material was obtained through uniaxial compression testing.A uniaxial compression simulation model was established using the method of rapid particle filling.The particle bonding parameters were calibrated based on the results of the compression test to obtain the microscopic bonding model parameters of the brake pad particles.(2)By using fractal theory,the micro model of 3D rough surface profile of brake disc was generated,and the influence of fractal dimension on rough surface topography was studied.Represent surface roughness using the least squares centerline as the reference line,and establish a solid model of the three-dimensional rough surface using 3D modeling software.Characterization of micro wear of brake discs based on Hertz elastic contact theory and Archard wear empirical formula.Establish a micro simulation model of the disc brake interface by combining discrete element and finite element methods,and verify the feasibility of the simulation model through friction and wear tests of the disc brake.(3)Based on the micro simulation model of the braking interface,the micro contact form and force state of the brake pads and brake discs were analyzed.Based on the EDEM Workbench joint simulation analysis of the stress and strain distribution on the surface of brake discs,the influence of braking parameters on the friction characteristics of brake pads and brake discs was studied.The results show that as the braking pressure and sliding speed increase,the force on the brake pad particles and brake disc increases,and the maximum stress and strain of the brake disc increase.(4)Based on the micro simulation model of the braking interface,the micro wear form and evolution process of the brake pads,as well as the variation law of the brake disc wear rate,were analyzed.Analyzed the generation process and distribution pattern of wear debris,and studied the impact of braking parameters on the wear of brake friction pairs.The results show that with the increase of braking pressure and sliding speed,the number of wear particles and bond fracture of the brake pads increases,the wear rate of the brake discs increases,and the wear of the brake interface becomes more severe.This thesis studies the micro contact friction process between the brake pads and brake discs of high-power disc brakes,analyzes the wear law of the braking interface,and explores the influence of braking parameters on the friction and wear of the braking interface.These studies provide a theoretical basis for improving the friction and wear performance of the braking interface.