Research On Diagnose And Optimization Of Vehicle Structure Road Noise Based On Methods Of TPA

As computer technology continues to mature,automotive design has evolved from the initial experience and test data to the use of computer simulation for positive development.While meeting the design accuracy,the design cycle and design cost have been greatly reduced.However,due to the limitation of computational efficiency and nonlinear unit model accuracy,the road noise problem is difficult to predict in the early development of NVH.At present,there is no comprehensive research method for the positive development of road noise.Therefore,it is of great engineering significance to establish a complete technical system for diagnosis and analysis of structural road noise of vehicles.This thesis analyzes the structural noise of road noise and analyzes the transfer path of its low frequency noise.Taking a SUV as the research object,the frequency of the structural road noise problem is first determined by means of experimental tests.Through the noise synthesis method,the main transfer path of the structural road noise is diagnosed and analyzed using the transfer path analysis theory.The structural road noise transfer path model was established.Based on the results of contributions from different paths,a further local transfer function analysis was performed on the bottom plate system to provide benchmark data for subsequent simulations.Using a combination of finite element and multi-body dynamics,a new modeling method is proposed.A rigid-flexible coupling model of the chassis is established,and the vibration transmission letter of the chassis system is analyzed.The calculated vehicle body attachment point excitation is loaded into the finite element model,and the interior noise value is finally obtained.The contribution of the transfer path contribution of the noise peak is analyzed.Through the test data and the simulation data,the accuracy of the simulation model is verified.Using the method of identification of the bushing parameters,the dynamic stiffness model of the nonlinear rubber unit of the chassis is established,and the dynamic stiffness transfer function of the elastic element in all directions is obtained.A bushing dynamic stiffness model is used to simulate the bushing connection,reflecting the dynamic characteristics of the chassis suspension and improving the calculation efficiency.Based on the analysis of the results of the transfer path contribution of the problem peak,the model of the transfer function of the chassis system is benchmarked,and the modals of the computing subsystem are analyzed.The problem components on the various transfer paths are diagnosed and an optimization scheme is proposed.The front suspension damper spring and the rear suspension trailing arm bushing,the rear stabilizer bar,and prototype parts were tested and verified.The effectiveness of the optimized plan was verified by the actual vehicle road test.