Analysis And Optimization Design Of Vibration Characteristics Of Electric Vehicle Powertrain Mounting System

NVH problem of electric vehicle has a long history.Electromagnetic vibration and gear meshing of gearbox cause high frequency vibration and noise of power assembly,which seriously affects the driving and riding comfort of vehicle.Mounting system is one of the main transmission paths of Powertrain vibration.At present,single-layer vibration isolation is the main method in the mounting system of electric vehicle.In order to improve the vibration isolation ability of the mounting system of electric vehicle in the high frequency,this paper starts with the vibration isolation mode of the mounting system,applies the small intermediate mass vibration isolation to the mounting system of electric vehicle,and analyzes and optimizes the vibration characteristics.The specific research contents are as follows:First of all,aiming at the problem of high frequency vibration and noise of electric vehicle powertrain,starting from the vibration transmission path,combined with the excellent vibration isolation ability of double-layer vibration isolation system in high frequency section,the small intermediate mass vibration isolation system is applied to the mounting system of electric vehicle.Secondly,the dynamic model of the mounting system of the electric vehicle is established,and the expression of vibration energy transfer of the mounting system is derived by the transfer matrix of the subsystem and the overall synthesis method,and the mode of the mounting system is analyzed.Then,the vibration transmission characteristics of the irregular and complex elastic foundation mounting system in the project are studied.The method of combining finite element analysis and vibration power flow calculation is used to obtain the complex elastic foundation modal information through the finite element software and substitute it into the elastic foundation admittance.In the matrix,the vibration energy transfer spectrum transmitted to the complex elastic foundation is obtained,and the influence of the basic structure characteristics on the vibration transmission of the mounting system is studied.Through theoretical calculation and ADAMS/Vibration analysis module,modal analysis is carried out on the electric vehicle mounting system to obtain information such as the natural frequency and energy decoupling rate of the system,and the influence of the basic elasticity on the natural frequency of the mounting system is discussed.Combined with an example,the influence of system parameters on the vibration transmission characteristics of the mounting system is studied.Finally,using MATLAB and ISIGHT software integration to optimize the design of the mounting system.The optimization goal is to take the weighted sum of the energy decoupling rate in the direction of 6 degrees of freedom of the powertrain as the optimization goal,the three-dimensional stiffness value of the elastic element and the quality of the intermediate support are selected as design variables.The insensitive variables in the design variables are eliminated through sensitivity analysis,and the adaptive simulated annealing algorithm is used to optimize the design variables.Taking vibration energy as the evaluation index,the optimized design plan is compared with the original plan.Finally,the Monte Carlo method is used to analyze the robustness of the optimized design variables.The results show that the robustness of the optimized design variables meets the engineering requirements...