Thermal-Structure Coupled Simulation And Life Research For A Automotive Disc Brake

With the rapid development of expressway and growing auto possession, traffic accident also increasing all the time. Braking system is an important part of car. which directly affect the safety of auto. Disc brakes braking process is a typical coupling process ralated to thermal-structure,which have important parts on the braking system involving vibration and noise, thermal fatigue. It is the important development car brake design content, and disc brake's characteristics of thermal-structure coupling now being widespread concern.Taking a car's front disc brake system for example, in accordance with the actual size of the disc and the pad.and consider the unity between them for a calculation model. Fully considers the coupling problem between the temperature field and stress field, and established a FEM model of 3-d transient temperature/stress field. Simulate the trueer field of disc brake braking process by nonlinear finite element software ABAQUS. Considering the braking process of convective heat transfer boundary conditions and brake disc dynamic parameters change and other factors In simulation process. This paper studies the brake disc surface temperature and thermal stress intermittent change as a result of the impact of heat mobile face under emergency brake conditions,and the mutual coupling problem between temperature field and stress field.The temperature distribution in the brake shows the nonaxi-symmetric effects and possesses a sharp gradient in both axial and radial directions.The great thermal stress is caused by the sharp gradient. And thermal stress will directly influence the contact pressure and in turn affect temperature field distribution.Based on the theoretical basis of friction heat production, researched brake disc's regularity of distribution about both temperature field and stress field by calculating disc 3-d transient FEM under emergency braking condition. After comparing the different calculation model (friction heat production model and heat flux model) to solve the process of brake thermal-structural coupling, and then simulated repeated braking condition of disc brake's temperature field and stress field by heat flux method. Discusses the brake disc radial cracking causes and possible thermal fatigue damage. Finally,based on the simulation results of temperature field and stress field under both of emergency brake condition and braking condition and repeated braking condition. Forecast the brake disc thermal fatigue life by using Mason-Coffin formula, and analyzed the affecting factors of life of braking discs.