Thermal-Stress And Strength Analysis Of Brake Discs In160km/h Wagon

Along with the great development of economy in China, there are higher request in freight transport, high-speed and heavy-load become more pressing needs in freight transport. Therefore, the large-scale and height-speed freights will be the main. Meanwhile, braking system also meets the new challenge. Traditional tread braking system can not meet the sharply increasing braking energy. However, the disc brake has larger power, its friction coefficient is stable, which can reduce the wheel tread wear. Therefore, the trains whose speed is faster than120km/h generally use disc braking system.No matter the routine braking or the emergency braking, the brake disc plays a key role, especially when emergency braking, it endures huge thermal load as a component of rubbing pair. The temperature of the surface becomes high because the heat which is produced by braking. Therefore, it has important meaning to analysis the temperature and stress field.This article analyses the braking disc in the high-speed freight of160km/h by finite element analysis software ANSYS10.0. According to the structure characteristics of the disc, It builds reasonable3D model and fully considered how to apply all kinds of loads. Energy-conversion method is used to determine the heat flux applied on the friction surface. It also finds a reasonable way to apply the heat coefficient based on the heat transfer theory. The temperature field, stress distribution and strength of the disc under an emergency brake are calculated.Specifically, the mainly work and conclusion of this paper is as follows:Considering the adhesion of braking restrictions and basic resistant force, the emergency brake of the freight train, which is composed by24trucks whose axle is18t, was calculated by identifying the parameters of160km/h freight. The results will provide necessary analysis boundary conditions for the thermal-stress analysis.The structure and thermal parameters of the brake disc are selected. The boundary condition of the brake disc is calculated based on the thermal analysis theory the three basic heat conduction ways and the mathematical model of temperature field)The thermal field of the brake disc is simulated on the base of the way how to apply the thermal load. After determining the brake disc boundary condition and loads, and applying the thermal field to the structure in multiple steps, the tress field is analyzed in once emergency brake in the thermal-stress coupled way. Then the radial and hoop stress in the brake disc is discussed. The results show that the brake disc bears press and draw stress. In the basic of static strength, the fatigue strength in three high stress parts of the brake disc is assessed. The result shows that all nodes that are selected fall in the curve of Haigh-Goodman. The fatigue strength meets the requirement. The high stress parts of the brake disc won’t appear crack. So in emergency braking, the static strength and fatigue strength meet the requirement when there are three discs in each axle of160km/h freight.