Research On Simulation Of Thermal Response Characteristics And Multi-field Model Test Of Disc Brake

Disc brakes are widely used in all kinds of vehicles.Because of its direct impact on the safety and reliability of vehicle,it occupies a pivotal position in the whole vehicle.In addition,with the unceasing advancement of vehicle speed,the heat generated in the process of braking increases sharply,which also puts forward higher requirements for the performance of disc brakes.Therefore,it is crucial to study the thermal response characteristics of disc brake during braking.In this paper,thermal response characteristics of brake disc are studied by simulation,and the correctness of simulation method is verified by the model test under the premise of considering the vibration caused by friction contact during braking process by using multi-field knowledge like mechanical vibrations,rotor dynamics,heat transfer theory and contact mechanics.Furthermore,several physical quantities such as the lateral displacement of a point on the brake disc surface,the temperature of a point on the brake disc surface,noise in the braking process,braking time,braking deceleration and so on are studied thoroughly through model test.First of all,taking urban rail vehicle as an example,kinematic and kinetic parameters during braking are calculated,and the three-dimensional flow field simulation of the brake disc based on these parameters is carried out in this paper.Through flow field simulation,the flow field distribution around the brake disc and in the vent during braking is obtained,the distribution of convection heat transfer on the whole domain surface is analyzed,and the convective heat transfer boundary conditions for subsequent solution of temperature field and stress field are acquired.Secondly,temperature and stress response distribution on the friction surface of the brake disc of urban rail vehicle are analyzed through three-dimensional thermo-solid coupling simulation considering the vibration deformation caused by friction contact.The phenomenon of thermal stress fluctuation on the friction surface of brake disc caused by vibration in early braking is explained through analyzing the axial displacement of relevant nodes,and the danger area on disc surface of intense axial vibration during braking is found.Finally,a small brake tester is designed and built to carry out multi-field model test research.Based on the data measured by test such as the lateral displacement of a point on the brake disc surface,the temperature of a point on the brake disc surface,noise in the braking process,braking time,braking deceleration and so on under different braking conditions,the amplitude and frequency characteristics of lateral vibration displacement and noise and the law of temperature change are studied,the evolution features of thermal response and braking performance parameters during braking are analyzed.In addition,the correctness of the simulation method is verified through comparative analysis of temperature history.The research in this paper has some guidance and reference significance for multi-field coupling analysis design and test of disc brake.