• CN:11-2187/TH
  • ISSN:0577-6686

›› 2005, Vol. 41 ›› Issue (7): 225-230.

• 论文 • 上一篇    下一篇

轿车车室声固耦合系统的模态分析

马天飞;林逸;张建伟   

  1. 吉林大学汽车工程学院;北京理工大学机械与车辆工程学院;吉林大学汽车动态模拟国家重点实验室
  • 发布日期:2005-07-15

MODAL ANALYSIS FOR FLUID-STRUCTURE INTERACTION SYSTEM OF CAR CAVITY

Ma Tianfei;Lin Yi;Zhang Jianwei   

  1. College of Automobile Engineering, Jilin University School of Mechanical and Vehicle Engineering, Beijing Institute of Technology National Laboratory of Automobile Dynamic Simulation, Jilin University
  • Published:2005-07-15

摘要: 车室声学模态分析是汽车NVH特性研究的重要内容,识别系统模态对避免声学共振、降低车内噪声有重要意义。利用有限元法建立某轿车车身结构和车室空腔模型,并建立了考虑结构与空气之间相互作用的车室声固耦合系统模型。列出三个系统的有限元方程式,使用MSC.Nastran软件对三个模型的模态进行仿真计算,对结构的模态频率和变形部位、空腔声学系统的声学模态频率和声压分布情况以及耦合系统中结构和声学空腔模态频率和振型的变化进行了详细分析。测量车内纵向对称面上的等声压线以验证仿真结果。结果表明:结构与空气的相互作用将改变原系统(车身结构或车室空腔)模态的频率和振型,并将引起另一个系统产生相应模式的振动;系统第一阶声学模态为纵向声学模态,其振型的试验结果与仿真结果在分布特点、变化趋势等方面符合较好。

关键词: MSC.Nastran, NVH, 仿真, 模态分析, 声固耦合

Abstract: The acoustic modal analysis of cavity is the important matter on vehicle NVH performance study. Identifying system mode is of importance to avoid acoustic resonance and reduce interior noise. The body structure model and the cavity model for a car are built using FEM. Fluid-structure interaction (FSI) model of body system that considers the interaction between structure and air is built. The FE equations for three systems are listed. Making use of MSC.Nastran software, modal analysis is simulated for the three models. The modal frequency and distortion section of structure, the acoustic modal frequency and sound pressure distribution of cavity as well as the change of the modal frequency and shape for the structure and cavity in FSI system are discussed in detail. The equal-sound-pressure- curves on the longitudinal symmetry surface of cavity are measured for validating the simulation. The results show that the interaction between structure and air can change the modal frequency and shape of original system (body structure or cavity), and can bring another system to vibrate in a particular pattern. The first acoustic mode of the system is a longitudinal mode. The distribution and trend of the modal shape, which come from test, are accord with the simulation result.

Key words: Fluid-structure interaction (FSI), Modal analysis, MSC.Nastran, Noise vibration harshness (NVH), Simulation

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