固定界面动态子结构方法研究车内噪声问题

随着社会的发展，降低车内噪声越来越受到人们的重视。由于整车结构复杂，本文采用包括软子结构的动态子结构方法，把整车模型划分为多个子结构，包括动力总成子结构、副车架子结构、车身与车内声场耦合子结构、非簧载质量子结构及多个线性和非线性软子结构等。采用固定界面模态综合法，建立整车结构车内声场流固耦合动力学模型。对于车身与车内声场耦合子结构，由于其总质量和刚度矩阵为非对称矩阵，传统的模态叠加法不能应用到耦合系统中，本文引入了左特征向量的概念，用左特征向量左乘原方程，使耦合系统微分方程得到解耦。在已建立的总系统动力学模型基础上，在时域内对前后轴分别激励时汽车振动和车内噪声特性进行仿真模拟，并通过台架试验对仿真结构进行验证。

Research of Automobile Interior Noise by Fixed Interface Dynamic Substructure Method

Along with the society development, lower automobile interior noise is considered by more people. For total car construction is complicated, dynamic substructure method which contained soft substructures was used to seperate the total car body into some substructures including engine substructure, engine cradle substructure, car body and its cavity fluid interaction substructure, mass substructure not supported by suspension and some linear and nonlinear soft substructure ect. The fluid-structure interaction dynamics model of total car was established by fixed--interface mode synthesis. For the mass and stiffness matrix of car body and car acoustics interaction substructure are un-symmetry, the tradition method of folding mode cannot be used, so the concept of left mode vector was induced, and the interaction equation of this system was broken up by this vector. With the dynamics model of whole system, the properties of automobile vibration and interior nosise caused by the excitation of front and rear axles were simulated in time areas. At last, the simulating results were verified by the test in laboratory.