Acoustic-structural Coupling And Panel Acoustic Contribution Analysis On Low Frequency Vehicle Noise

In order to improve the riding comfort, NVH technology is used for achieving the desired vibration and acoustic performance during the development of new vehicle. Using the acoustic finite element method, the low-frequency noise of vehicle and the method to reduce the interior noise were analyzed.According to the finite element method, the finite element models of a commercial vehicle body, the compartment cavity and coupling system considering the interaction between the structure and air were established by HyperMesh.The modal analysis of BIW structure was researched by Abaqus, and the natural frequencies and mode shapes could be obtained. The frequency response of structure was analyzed based on modal analysis.Car cavity acoustic modal analysis is an important part of vehicle vibration and noise characteristics, identifying the acoustic modes of the cavity systems is important to avoid acoustic resonance and reduce the interior noise. Based on the acoustic modal analysis theory, the free modal of the acoustic finite element model was analyzed by using the LMS the Virtual lab software, and the natural frequencies and mode shapes of the cavity compartment could be obtained.The results of the frequency response analysis were used as boundary conditions. Interior acoustic pressure distribution and the acoustic contribution of the panel were calculated by using the acoustic transfer vector method. Amplitude phase diagram method and calculation panel acoustic contribution coefficient method were adopted to find the largest acoustic contribution panel, which may have an important impact on low frequency noise of the vehicle and provide reference for the further improved.Frequency response analysis between20to200Hz on vehicle acoustic-structural coupling model was analyzed by using LMS Virtual.Lab software. The sound pressure field distribution of interior noise, and forecast the sound pressure response of the measuring point could be obtained. The effect on vehicle noise by the thickness of panel and the arrangement of absorption material was analyzed, and the method to reduce the interior noise was researched. As a result, good acoustic performance could be achieved by improving the structure.