结构声腔耦合系统的振型耦合机理研究(英文)

The Mode Shape Coupling Mechanism of the Structural-acoustic Coupled System

轿车车内200Hz以下的低频噪声非常恼人,它主要是由结构振动引起的,所以研究结构声腔的耦合机理非常重要。而结构声腔的耦合主要包括振型耦合以及频率耦合两个方面,其中振型耦合可用振型耦合系数描述。首先基于腔内声压计算公式,获得了仅适用于规则结构或者声腔的振型耦合系数的解析计算公式。而对于不规则对象,推导并验证了一种振型耦合系数的新的数值计算方法。然后重点分析了某简单结构声腔耦合系统的振型耦合系数特征,发现结构声腔的振型相似系数和振型复杂系数是影响振型耦合系数的关键,振型相似系数越高、振型复杂系数越低,则振型耦合系数越大、结构声腔耦合程度越强,这就是某简单结构声腔耦合系统的振型耦合机理。

It is annoyed when the interior noise at frequency is below 200 Hz in cars . It is for a large part the result of structure vibration. So the study of the structural-acoustic coupling mechanism is very important. The coupling includes the mode shape coupling and the frequency coupling. This paper focuses on the analysis of the mode shape coupling mechanism. The mode shape coupling coefficient （MSCC） is used to describe it. The equation of MSCC is focused depending on the formula of the interior sound pressure, which is mainly applied on certain regular shaped structures or fluids. Consequently the new method through numerical process to calculate MSCCs of regular and/or irregular ones is deduced and validated. The MSCCs of a simple regular shaped coupled system is analyzed. And the conclusion comes out to be that the mode shape similarity and complexity between the structure and the fluid on the contact surface mainly affect MSCC. The higher the similarity and the lower the complexity on the interaction surface, the bigger is the MSCC and the stronger is the coupling degree which is the mode shape coupling mechanism of the structural-acoustic coupled system.