Analysis On Impacts Of Train Braking Heat On Braking Noise

Railway is the lifeline of our country’s economy. With the development of country’s economy and demands, high-speed and heavy-haul railways have become two significant ways adopted by China to improve the railway transport capacity. However, the safety and the comfort problems of high-speed and heavy-haul trains follow. The typical problem of train braking systems is braking heat and braking noise. The braking temperature can reach to 400℃, which will lead to fatigue damage of the brake elements. Meanwhile, the braking noise of trains make passengers feel uncomfortable. Therefore, it is significant to study the temperature and noise of train braking.A finite element model of braking heat and braking noise of an axle-disc brake system is established based on the thermal-mechanical coupling principle and the mode coupling theory. True constraint conditions are taken into account in the model. Some unnecessary procedures are simplified by the main stream method. The following results are obtained:1. The CAD model of axle-disc braking system is established by CAD software, the temperature field and stress field of braking system, and variation of temperate and stress can be gained by the simulation of software ABAQUS. Finally, the influence of the axle load, train speed and brake deceleration of train on temperature is analyzed. It is found that the temperature and stress is increased rapidly but decreased slowly during braking. The braking temperature is increased with the increasing of axle load, train speed and brake deceleration.2. The main frequency of braking noise can be obtained by the complex eigenvalue and transient dynamic methods. The results obtained by the transient dynamic method are agreed with the results obtained by the complex eigenvalue method.3. Braking heat has a big influence on braking noise. It mainly affects the order of braking noise, the value of frequency and the occurrence propensity. Thermal-Mechanical coupling effects must be considered in the braking noise simulation analysis to improve the prediction accuracy and to reflect the time-varying characteristics of the braking noise. The influences of the elastic of material, expansion coefficient and the superposition of two factors are studied by the complex eigenvalue method. It is found that the braking temperature has a deep influence on the material characters, volume of brake elements and tensile stress, and the expansion coefficient of the material has a leading influence on braking noise. It is verified that braking heat has a big influence on braking noise in both the amplitude of braking noise and the main frequency of braking noise by the transient dynamic method. The change of the main frequency is decreased firstly, but increased lastly during braking, which is in coincidence with the trend obtained by the complex eigenvalue method.