The FEA And Experimental Study On Emergency Braking Of Brake Disc Based On The Theory Of Thermo-Mechanical Coupling

The ventilated disc brake is the core component of the passenger car braking system,it plays an important role in the safety and comfort of passenger cars,and the braking process of the brake disc is a typical thermo mechanical coupling process.In order to analyze the transient characteristics of temperature field and stress field during brake disc braking,and predict the thermal fatigue life of the brake.In this paper we choose the brake whose speed is 100km/h and to be stopped in the shortest time,and established a finite element model of three-dimensional transient heat engine coupled simulation of the brake,and the simulation analysis was carried out.At the same time,we obtained the radial temperature changes of the brake disc and the service life of the brake disc are by bench test,and we also compared and analyzed the simulation and test data.The main research contents are as follows:(1)The simulate of the thermal-mechanical coupling model.Based on the analysis of the thermo mechanical coupling of ventilated disc brakes at home and abroad,we confirmed the convective heat transfer and heat flow input boundary conditions under emergency braking conditions;and we established the three-dimensional transient temperature field heat conduction equation and the three-dimensional simplified model of brake under Catia and the finite element simulation model of brake system under Abaqus;then we analyzed the distribution characteristics and coupling relationship of temperature field and the stress field of brake disc in different directions during emergency braking.(2)The life prediction.The general cause of the crack in the radial direction of the disc surface under cyclic alternating stress were discussed,which was based on the simulation results;and we predicted the thermal fatigue life of the brake disc is by empirical formula under the condition of emergency braking.(3)The experimental study.The bench test platform about the brake and set the test parameters under the corresponding operating conditions were built,and we measured the surface temperature of the disc brake process in the radial direction by the infrared temperature sensor,and we also tested the final service life of the brake disc.Simulation analysis and experimental results show that:(1)In general,the stress field and the temperature field showed a slower downward trend after a faster rise;Stress field and temperature field on the contact area showed a jagged wave dued to the continuous alternation of moving heat input and convection heat dissipation and the number of fluctuations was consistent with the number of rotating rings;the distribution characteristics of temperature field and stress field were similar and the maximum principal stress appeared later than the highest temperature.(2)The surface of the brake disc will be the initial position of the crack,and then developed in depth;The brake disc had an emergency braking life of 1454 times when the initial speed was 100 km/h and the braking pressure was 3.46 Mpa;(3)The simulation of the surface temperature of the brake disc in radial direction was slightly higher than that of the test temperature;the service life of the test basically coincided with the predicted life.