Simulation Analysis Of The Vehicle Body System NVH Performance

This paper tries to analyze and optimize NVH basic function of the automobile body structure based on a new automobile developing program of a domestic automobile factory by using finite element software such as Altair Hypermesh,MSC.Nastran and etc.,so as to achieve it and shorten the product's development cycle.The tasks are mainly shown as follows:Firstly,the theoretical knowledge and experimental method of the model are described in detail.On the basis of STEP format file,the finite element model of the body in white is established and its free modal features are analyzed,which obtains the main vibration model and its frequency,whose accuracy has also been tested through the comparison between the results of the simulation model and the experimental one.Secondly,based on the body in white model,a trimmed body model and acoustic cavity model are set up with the assembly of closures,seats and simplified interior model.The potential problems are illustrated through the modal analysis of cavity and the distribution of sound pressure.In the next section,in the view of the trimmed body structure model,the dynamic stiffness of the main attachment is calculated and the reason of its low stiffness is figured out and therefore effectively improved.Also on account of the acoustic-structure coupled model,this paper calculates the noise transfer function from the attachment to the driver's right ear,analyzes and verifies the frequency range of the failed transfer attachment without the influence of the cavity,so that a method of improving transfer function is put forward to and the latter design and optimization of the body had a foundation,based on the result and optimization method of stiffness.