Thermal-mechanical Coupling Simulation Analysis And Test Characterization Of Bionic Brake Disc For High-speed Light-load Vehicle

As an important component for ensuring safe and reliable vehicle operation,the brake disc is accompanied by strong thermal-mechanical coupling phenomena during its working process.Especially for high-speed light-load vehicles,the heat generated by the enormous kinetic energy during braking cannot be dissipated into the surrounding air in a short period of time,resulting in severe frictional wear and thermal damage to the brake disc.This accelerates the loss of the brake disc’s service life.Therefore,it is necessary to propose an optimization method for the surface structure of the brake disc for high-speed light-load vehicles’ braking conditions and develop brake discs suitable for these vehicles.This article mainly focuses on the following research:(1)Firstly,based on the principles of engineering biomimetics,three biomimetic braking discs are created by constructing non-smooth structures such as elliptical pits,straight grooves,and crescent-shaped pits on the smooth surface of the brake disc.These structures are inspired by the body surface morphology of dung beetles,shells,and Procambarus clarkii.A thermal-mechanical coupled finite element model of the biomimetic braking disc is established using ANSYS software.The temperature and stress fields of the brake disc are simulated under initial velocities of 120 km/h,160 km/h,and 200 km/h to investigate the effect of non-smooth structures on the temperature and stress distribution characteristics of the brake disc.The results indicate that the installation of non-smooth structures can effectively enhance the brake disc’s heat dissipation ability and suppress the temperature and stress gradients in the radial and axial directions,thereby reducing the occurrence of issues such as cracks and thermal damage.(2)A comparative study is conducted on the tribological behavior of specimens with different non-smooth surface structures under the same working conditions.The effects of different surface structure characteristics on the friction coefficient,wear amount,surface temperature,and friction noise of the specimens are explored.Among them,the straightgrooved specimen with an air inlet duct performs better in terms of stable friction coefficient and temperature rise suppression compared to the straight-grooved specimen without an air inlet duct.(3)For the straight-grooved brake disc,which exhibits good performance in simulation analysis and test characterization,an improvement scheme is proposed.A multi-objective optimization mathematical model for the straight-grooved brake disc is constructed using nested Latin hypercube sampling,polynomial response surface proxy model,and crossvalidation evaluation method.The design parameters of the straight-grooved brake disc are obtained by applying the non-dominated sorting genetic algorithm II(NSGA-II).By comparing the design schemes before and after optimization,the feasibility and effectiveness of the optimization method for the straight-grooved brake disc are verified,providing a theoretical foundation and technical reference for the development of biomimetic braking discs suitable for high-speed light-load vehicles.