Thermal Structure Coupling Analysis And Structural Optimization Of Disc Brakes

The thermal engine coupling effect of the brake will reduce the service life of the brake and seriously affect the braking performance of the brake system.The thermal mechanical coupling theory of the brake disc of a passenger car under the emergency braking condition is researched in this paper.The main research contents of this paper are as follows:(1)The basic theory of coupling analysis of thermal mechanism is described:contact analysis,friction heat generation and thermodynamic theory;The transient heat conduction equation of the brake is established,including the temperature field heat conduction equation and the thermal stress calculation;The solution method of brake thermal coupling is discussed.(2)The purpose of simplifying and dividing the mesh is to reduce the amount of calculation in finite element analysis;The braking condition of disc brake is analyzed and the braking parameters are calculated.The initial braking conditions are obtained,and the convection heat transfer coefficient and heat flow distribution coefficient are obtained;In the finite element software,the material parameters of each part are set,the contact between each part of the brake is set,the boundary conditions and load steps of the brake are set,and the thermal structure coupling model is established.(3)The finite element model is imported into ABAQUS for simulation analysis of temperature field and thermal stress field.The results show that the nodal temperature curve of the brake disc surface changes in a zigzag shape.Subsequently,the bench test is carried out to verify that the thermal structure coupling model of the brake has high accuracy and can be used to predict and study the thermal structure coupling characteristics of the disc brake.(4)According to the established finite element model,the brake structure is optimized based on genetic algorithm.The optimum value of the design variable parameters of the brake disc is obtained by using the optimization method with the minimum temperature rise and the minimum thermal stress caused by the temperature rise as the optimization objective under the same braking conditions.The maximum temperature of the brake disc before optimization is 275.8℃,the maximum temperature of the brake disc after optimization is 261.3,the maximum stress value of the brake disc before optimization is 185.9 MPa,and the maximum stress value after optimization is 176.1 MPa.After optimization,the maximum temperature of the brake disc is reduced by 5.25%,and the maximum stress value of the brake disc is reduced by 5.22%.