Research On Dynamic Of Disc Brake System In Train Considering Temperature Factor

The disc brake system is a basic braking method adopted by most high-speed trains all over the world.It achieves the purpose of train deceleration,parking or inhibiting train movement through friction vibration.However,in actual working conditions,the braking system is affected by many non-linear factors such as contact surface pressure,braking speed,temperature and wear state of braking components,which results in strong non-linear vibration and noise pollution of the braking system.Moreover,the high temperature of the friction pairs produced in the braking process,especially the temperature rise caused by emergency braking of trains under high speed,has already affected the braking ability of braking system and driving safety.Therefore,the study of the temperature change between the contact surfaces and the dynamic behavior of the disc brake system during the friction braking process can provide a theoretical basis for the optimal design and system control of the system.In this paper,the braking part of train disc braking is taken as the research object.According to its working principle,a single-degree-of-freedom disc braking system is established at first.and its dynamic analysis is carried out.Then,considering the dynamic changes of the disc itself in the braking process,a two-degree-of-freedom disc braking system model is established.The influence of different friction models on temperature and dynamic behavior of braking system is analyzed by combining system diagram with time history diagram.The main contents are as follows:For the disc braking system with single and two degrees of freedom,firstly,the motion equation of the train is treated without any dimension,and then the state equation of the system is written by the coupling relationship between temperature and friction coefficient.The friction force produced by the system during braking is controlled by Coulomb friction model and Dankowicz dynamic friction model respectively.Using the fourth-order variable step Runge-Kutta algorithm is used to solve the state equation,the numerical simulation is carried out by C language programming,the symmetry is programmed in C language.The control variable method is used to analyze the influence of some key parameters of the system on the contact surface temperature and friction coefficient of the braking system under different friction models,and the dynamic behavior of the braking system under the influence of the temperature.The results show that the higher the initial braking speed,the higher the contact temperature of the system,the larger the friction coefficient,and the maximum value of both at the same time,the linear change between the two,and the higher the initial braking speed,the system The higher the velocity and displacement amplitude,the stronger the vibration,but the chattering phenomenon of the system is more obvious at low speed;and the higher the brake pressure,the higher the contact temperature of the system,the larger the friction coefficient and the maximum value.The time required is longer and the vibration is more intense,and equal amplitude vibration occurs at a certain pressure.In addition,compared with the Coulomb friction,the value of the contact surface temperature and friction coefficient of the braking system under the action of Dankowicz also increases with the increase of the initial braking speed and the braking pressure,but the time required is shorter.At the same time,the dynamic behavior of the brake system becomes more complicated and the chattering phenomenon is more obvious.