Study On The Degree Of Partial Wear Of Brake Pads And Simulation Calculation

The eccentric wear of brake pads seriously affects the safety of trains and the service life of the brake pads.The study of eccentric wear mainly adopts the experimental test method,but it is easily limited by the actual test conditions,and it is difficult to obtain the work from a quantitative perspective.The influence of conditions on the degree of partial wear.Therefore,the appropriate characterization method for the degree of eccentric wear of brake pads is explored,combined with numerical simulation methods to calculate,and the calculation formula of the relationship between the degree of eccentric wear and braking conditions is summarized,which is useful for understanding the vehicle caused by excessive eccentric wear of brake pads.The hidden danger of braking safety is instructive.Aiming at the characterization and calculation of the degree of eccentric wear of brake pads,using ABAQUS software,aiming at two friction modes of constant speed and inertia,the test speed is 80～140km/h,the braking pressure is 0.3～0.9MPa,and the wear coefficient is 1×10^-14～1.5×10^-13Pa^-1,the relationship between the eccentric wear of the brake pads and the braking time and braking conditions is simulated,and the calculation formula of the eccentric wear of the brake pads is established,and the following results are obtained:（1）The angle between the normal vector of the loading surface and the normal vector of the friction surface is defined as the eccentric wear of the brake pad,which can effectively express the radial and circumferential eccentric wear of the brake pad.（2）Utilizing the ALE adaptive grid function of the ABAQUS software and writing the UMESHMOTION user subroutine,the numerical calculation of the partial wear and the partial wear of the brake pads is realized.（3）Under the braking conditions studied in this article,a formula for calculating eccentric wear is proposed:（?）（?）（?）（4）The formula for calculating the partial wearΔh between two points is given:（?）（5）The eccentric wear form of the brake pads is that the circumferential eccentric wear is greater than the radial direction.The reason is that the additional torque on the brake pads causes the uneven distribution of the friction surface contact pressure.This pressure deviation is the main factor causing the circumferential eccentric wear of the friction surface.The difference in the frictional linear velocity in the radial direction causes the radial eccentric wear of the brake pads.（6）The overall eccentric wear of the brake pads is relatively close to the circumferential eccentric wear.In the early stage of braking,the overall eccentric wear increases linearly with the increase of the braking time.In the later stage of braking,the braking speed decreases,which has an impact on the eccentric wear.Not obvious.The radial eccentric wear is 1/5 of the circumferential eccentric wear.This value does not change significantly as the braking time increases.（7）Compared with the three factors of brake pressure,initial speed and wear coefficient,the wear coefficient has the greatest influence on the eccentric wear,followed by the brake pressure,and the least influence is the initial brake speed.