Research On Tread Brake Heat Injury Of Freight Wheel

With the development of the high speed and heavy load, the kinetic energy of the rolling stock becomes higher and the brake capability is very important to guarantee the safety of cars. For the freight train, the main braking method is still the tread braking. The kinetic energy is transferred to heat energy by the friction between the shoe and the wheel tread which is the mainly parts of the basic brake system. So wheel tread especially for high-speed and heavy-loaded wheel is working at the condition with strong friction, high temperature load and high brake and centrifugal force. Above all, the reliability of the tread brake directly influenced the operating safety of train; thermal fatigue is main reason for the wheel invalidation.The thermal fatigue research about the engineering structure has been developed for a long time. The research object of this article is thermal fatigue of wheel tread brake.The contents of this paper can be summarized as follows:1. the paper introduced material and performance of the wheel which used by many countries; then contrasted the chemical component and the capability of the wheel material and expounded the manufacture method, process and technics of the wheel. Then analyzed the main invalidation form and the invalidation engender mechanism.2. basing on the mechanics elastoplastic constitutive model of CL60 steel, which is obtained by the study research, this article do the numerical simulation for the stress field and temperature field of wheels under increasing heat load3. researched the forecast method of wheel heat fatigue lifetime, then studied the wheel tread damnification analysis and lifetime forecast method based on elasticity analysis. Distilled the load for the simulation result, and then half-quantitative calculated the germination life through local stress-strain method.