Analysis Of Flutter And Noise For Disc Braking System

Brake system is an important guarantee for the safety operation of the railway vehicle.At present, most of the high speed EMUs in the world take disc brake dynamic system as the basic braking mode. The flutter that produced during braking can cause a certain extent influence to the brake system, frame as well as the parts of car body. The noise that makes during this course will cause the passengers’ comfort decline, it also increases the noise pollution along the railway. Therefore, the exploration towards the disc braking flutter and noise mechanism of the disc braking system has some practical significance. Furthermore,this thesis makes an exploration of the flutter phenomenon and the noise problem of the railway vehicle disc brake system by the method of the numerical analysis.According to the working principle of the disc brake system as well as the analyzed the interactions between the brake disc and brake pad, a two-degree-of-freedom system dynamic model is established. It also analyzed the steady and stick-slip motion of different braking initial speed and braking pressure of the system; the model of Matlab/Simulink is set up when the factors of the track irregularity is taken into consideration. Besides, the state of the system under different braking initial speed and braking pressure under the influence of random excitation is also analyzed.In the process of braking,the disc brake system produced by friction flutter also has some influence on the frame and car body, the model of the disc brake system is combined with frame and 1/4 car body, a simulation model of Matlab/Simulink with three-degree-of-freedom system is therefore set up. Meanwhile, this thesis selects a Stribeck model with negative slope of friction phenomenon as friction of the system, the steady and stick-slip motion condition of the disc brake dynamic system is also analyzed. In order to simulate the vibration of vehicle brake system precisely. The six levels of the USA track spectrum as a random excitation was applied, It also discusses Different braking conditions of the brake pad, frame and car body in the case of low initial speed and stronger braking pressure.In order to research the mechanism of brake noise. Using 3D modeling software to establish the system of entity modeling makes modal analysis to brake disc, pad and the brake system of the two coupling with finite element software ABAQUS, it can be concluded that the unstable frequency of the disc brake system and the modal vibration mode corresponds with it. At last, it provides a transient dynamic analysis of the process of disc braking dynamic braking system with the theory of finite element analysis and the fundamental cause of the noise can be reached.