Development And Application Of Drum Brake Assisted Calculation And Analysis System

Among the casualties caused by vehicle safety performance in the country,accidents caused by drum brakes account for the majority,which are harmful to people's production and life.To solve the problems caused by the drum brakes,it's necessary to start from the structural design of the drum brakes.The structural design of the drum brakes based traditionally on the empirical analogy method cannot meet the needs of the present.Therefore,this paper develops a drum brake assisted calculation and analysis system for the theoretical calculation and finite element analysis of drum brakes,and the following research work has been carried out:(1)The working principle and structure type of the drum brake are introduced.According to the force analysis of the most commonly used cam-type leading-trailing drum brake,the calculation method and process of braking torque requirement,theoretical braking torque and driving force of the brake are obtained,which lays a foundation for the calculation part of subsequent system development.Combined with the calculation parameters and the actual structure of the drum brake,the brake drum,the friction plate and the brake shoe are parameterized,which lays a foundation for the subsequent parametric finite element analysis.(2)The relevant theories of drum brake in structural analysis,thermal analysis and thermal-structural coupling analysis are expounded,to obtain the computational analysis method suitable for drum brake finite element analysis.Analyzed the form of energy distribution during vehicle braking,and the boundary conditions(including heat flux,surface heat transfer coefficient and radiation heat transfer coefficient)of the brake drum transient thermal analysis are determined by the energy distribution method.According to the finite element analysis theory and the boundary conditions of the drum brake under various analysis types,the finite element analysis process of the drum brake under structural analysis,thermal analysis and thermal-structure coupling analysis is obtained.(3)Using the VB programming language combined with the APDL parametric language in ANSYS software,a drum brake assisted calculation and analysis system was developed.According to the theoretical calculation and finite element analysis process of the drum brake,the functional modules of the drum brake assisted calculation and analysis system are designed and implemented.The interface design of the drum brake assisted calculation and analysis system is carried out for each functional module.(4)Using have been completed the drum brake assisted calculation and analysis system to calculate the theoretical braking torque of the 3502 F drum brake,structural analysis,thermal analysis under 15 repeated braking condition and thermal-structure coupling analysis under one time emergency braking condition.Thus,the theoretical braking torque,the simulation analysis braking torque,contact pressure distribution on friction plate,temperature field and stress field situation for 3502 F drum brake was obtained,and the above results are analyzed and discussed in depth.Next,the bench test of the 3502 F drum brake was carried out.The test braking torque of this type of brake and the temperature rise curve of the brake drum under 15 repeated braking conditions were obtained through experiments.Compare the test results with the system simulation results to verify the accuracy of the drum brake assisted calculation and analysis system.