Thermal-Structure Coupling Analysis And Optimization Of The Electric Vehicle Disc Brake

Brake as the core part of the braking system of Electric Vehicle, which directly affectthe safety of the vehicle. The working process of the brake was a typicalthermal-structure coupling process. The surfaces of friction pairs would produce a lot ofheat while vehicles braking. It would make the surface oxidation, brake to generate hightemperature and thermal fatigue wear, and might lead to problems of disc thermalcracking and decline, so that the die life of the brake may be reduced and perhaps causethe large hidden trouble.Therefore, the heat-structure coupling analysis was of greatsignificance for the disc brake.Based on the electric car front disk brake as an example, researched the disc brakethermal structure coupling analysis and optimization.Firstly, according to the actual geometry size, a three-dimensional model of the discbrake which was required by thermal-structure coupling simulation could be establishedin ABAQUS, the analysis model is appropriately simplified and meshed，but thepremise was that the analysis precision must be ensure. Boundary conditions whichwere needed by the analysis would be calculated through the empirical formula and thetheoretical formula.Then, the thermal-structure coupling analysis of emergency braking condition couldbe implemented while using the finite element model which was established above, thedistributing situation of the coupled thermo-mechanical state of the transienttemperature field and stress field could be revealed. In an emergency braking condition,the temperature field of the disk first appears non axisymmetric distribution in radialand axial direction, there were large temperature gradients, and the circumferentialtemperature difference was small. With the increase of the brake time，the temperaturefield distribution of the disc would gradually tend to be axisymmetric. Equivalent brakedisc stress was periodically increased mainly due to the effect of convection heattransfer and frictional heat, and the brake disc and the friction block position of themaximum stress was located in the middle position of the contact.Finally, design of experiment would be used to construct approximate model in orderto simplify the optimizational calculation. Sampled the optimization variables throughthe method of Optimal Latin Hypercube, then, two order response surface models couldbe established by the calculated data, so that the approximation model of the maximumstress, the maximum temperature and the maximum moment could be built. Applied Pointer Algorithm in Isight, took the maximum braking torque as a target, with thehighest temperature and the maximum stress and the maximum braking torque ofpreventing locking the front wheel and skiding as constraint conditions and fourstructural parameters of the brake disc as the design variables to optimize. The results ofoptimization need to be reanalyzed to verify the effectiveness. The results show that, inthe premise of ensuring the strength and temperature, the maximum braking torque isreached，the total volume and mass of brake disc and block is reduced, so that the effectof optimization is achieved.