NTF Analysis And Structure Optimization Design Of Pure Electric Bus Based On Acoustic-Structure Coupling

With the development of new energy vehicles and electrification,the NVH performance of pure electric bus has received great attention.Poor NVH quality will reduce the driver’s subjective driving experience.Compared with the traditional internal combustion engine vehicle,the NVH performance of pure electric bus is more prominent.The noise transfer function of the car body reflects the acoustic characteristics between the car body structure and the interior cavity.It can accurately predict through the acoustic structure coupling analysis in the car body design stage,so as to find and correct the problems in the design as soon as possible.In addition,compared with the traditional internal combustion engine bus,the load-bearing form and structure of pure electric bus body have changed greatly,so it is of great significance to carry out topology optimization in the body structure design stage.In this paper,a pure electric bus is taken as the research object.Under the guidance of the finite element analysis method of acoustic solid coupling analysis theory,the acoustic solid coupling model of the pure electric bus is established.On this basis,the NTF noise transfer function of the bus body structure is analyzed based on the acoustic solid coupling model.Finally,the body structure is optimized based on the structural topology optimization method.Firstly,according to the modeling criteria of the finite element model,the finite element model of the body structure and interior acoustic cavity of the pure electric bus is established,and the modal analysis of the model is carried out,which preliminarily verifies the accuracy of the model.Secondly,in order to reflect the interior noise level more intuitively,the finite element analysis model of sound structure coupling is established,and the model is excited at the right front mount,left front mount,left rear mount,right rear mount,left rear mount,right rear mount and motor mount respectively,and the sound pressure level response at the driver’s left and right ears is taken as the target value to simulate the sound structure coupling finite element model TF noise transfer function analysis,compared with the target value shows that the noise transfer function calculation results meet the needs of the company.Finally,based on the finite element model of the vehicle structure,based on the topology optimization theory of the finite element method,after applying the load of power battery group,motor,driver and passenger,the static condition is selected as the optimal condition,the strength of the optimized body structure is taken as the constraint condition,and the volume fraction after the model optimization is no more than 5% as the objective function,and the topology optimization is established The mathematical model is optimized by Optistruct software.The optimization results show that the weight of the body structure is 455.8kg and the mass is reduced by 5.3% on the premise of ensuring the static strength of the body structure.The optimization scheme is reasonable and effective.