Pressure Response Characteristic Study Of Diaphragm Brake Chamber

Brake chamber is a key component in pneumatic braking system of commercial vehicle.Its main function is to convert pressure energy of air into mechanical energy of actuator and its pressure response performance directly affects performance of pneumatic braking system.With the development of finite element analysis,computer-aided engineering technology for modeling and analysis of brake chamber can improve research and development efficiency,and at the same time can simulate and predict dynamic response characteristics of brake chamber.In this paper,pressure response characteristics of diaphragm brake chamber were analyzed in detail based on fluid-structure coupling theory,and following aspects were mainly completed:1.Structure and working principle of brake chamber were analyzed in detail.Mathematical model of pressure response of brake chamber was established according to flow characteristics of gas.And theoretical pressure response curve of brake chamber was calculated,which provided a reference for subsequence simulation analysis and testing.2.Rubber diaphragm is key element of brake chamber and is a composite material made of fabric and rubber.It is characterized by obvious nonlinear in the process of movement.In order to improve convergence of simulation,geometric model of representative volume element of fabric reinforced composite was established,results of stress and strain field of representative volume element were obtained by micromechanical finite element analysis.Engineering elastic constants of fabric reinforced composite were calculated by volumetric weighted average.3.Based on fluid-structure coupling theory,fluid-structure coupling finite element model of brake chamber was established,and changes of fluid pressure field during inflation and deflation process were analyzed.At the same time,brake chamber test bench was built,and dynamic response curve of brake chamber was obtained.Comparing with simulation results,rationality and correctness of simulation model in this paper was verified,which can provide a calculation basis for subsequent brake chamber simulation analysis,and source of error was analyzed in detail.4.In order to explore influence trend of structure parameters of brake chamber on its pressure response characteristics,an orthogonal test design was conducted on main factors,and orthogonal test results were analyzed by using range analysis method to obtain degree of influence of each test factor on pressure response time.At the same time,taking pressure response time as optimization objection,response surface optimization design method was used to optimize brake chamber structural parameters,and optimization results were compared with parameterized model results to verify correctness of response surface optimization method.In this paper,research method of pressure response characteristic analysis and structural parameter optimization design of brake chamber can provide theoretical guidance and technical reference for design and development of brake chamber.