The Whole Bus Modeling And The Internal Noise Prediction

The vibration and noise is characterized by an important indicator of quality automotive products, auto buses in particular. he researched object in this study is one kind of buses, and we research for the dynamic characteristic of the automobile’s configuration and the coupling sound field inside the automobile by finitude element method and boundary element method.This paper introduces the development of interior noise at home and abroad and the finite element theory, based on established bus skeleton model, with skin, glass and floor of the body structure model, interior cavity model and acoustic-structure interaction model. discretization of the above model, the formation of finite element modelStructure and acoustic field using dynamic analysis, dynamic characteristics of the vehicle body structure, vehicle acoustic characteristics of sound field room cavity, body structure-structure of cars room acoustic cavity coupled system of dynamic characteristics of the system. Modal analysis of body structure, vehicle acoustic cavity mode.Analysis of the structure in which the body can better grasp the modal vibration transmission and noise generating mechanism, then the interior noise prediction and diagnosis of noise sources, acoustic panel analysis provide the basis for contributions. Car room acoustic modal sound field cavity in the car design for the stage, to avoid the car room wall cavity acoustic resonance chamber with the car provided very valuable information to guide the initial board room acoustic design.Paper also analyzed the body in the engine structure excited by harmonic vertical excitation in the engine, the results obtained from the analysis:Vertical excitation in the engine, vehicle structural response of the vertical response of larger than the other direction, at a frequency of32Hz maximum peak occurred near the office are, and the response amplitude increased with the frequency gradually decreased, especially in the (32-35) Hz section, reducing the trend is clearly in the (32～38) Hz also appeared within several peaks, but relative to the38Hz peak is much smaller office. Also analyzed under the bus in the road excitation Harmonic Response Analysis. Vertical excitation on the ground, the vertical response of vehicle structures larger than the other direction of response, at a frequency of24Hz the maximum peak occurred near the office are, and the response amplitude increased with the frequency gradually decreased, especially in the (26-28) Hz section, reducing the trend is clearly in the (64-66) Hz also appeared within several peaks, but relative to the24Hz peak is much smaller office. Harmonic analysis aims to get all the nodes in different frequency excitation displacement solution, as the acoustic analysis of boundary conditions.