结构声辐射的源强声辐射模态分析方法

摘要

Velocity acoustic radiation modes can be used for solving the radiation problems of structures, but it is difficult to obtain the velocity acoustic radiation modes of complicated structures. In this paper, a method based on source intensity acoustic radiation modes is proposed. In this method, the continuous source intensity distributed on the surface of the structure is equivalently replaced by a set of simple source intensity distributions in terms of a simple source integration formula. Then, the set of simple source intensity distributions is used to construct a second order expression for the structural sound radiation power. In fact, this second order expression has defined a radiation resistance matrix, which eigenvectors constitute a set of acoustic radiation modes. Thus, decoupling of the total sound radiation power of the complex structure is realized. Given the expansion coefficients of the sound radiation modes, the sound pressure, normal velocities of particles and some other acoustic quantities in the acoustic field can be acquired by the superposition of the source intensity acoustic radiation modes. Analyses of a spherical sound source and a truncated-pyramid sound source show that the proposed method retains the advantages of the traditional acoustic radiation modes method and is more suitable for solving the sound radiation problems of the complicated structures.%为了解决不易获取复杂结构振速声辐射模态和利用其计算复杂结构外辐射声场困难的问题，提出源强声辐射模态分析方法。该方法利用简单源积分公式将结构表面连续的源强分布等效为一组简单源源强分布，利用这组简单源源强分布构造了结构辐射声功率2次型表达式，其2次型系数定义一个辐射阻矩阵，辐射阻矩阵的特征向量就构成了源强声辐射模态，从而实现复杂结构总辐射声功率的解耦。只要获得声辐射模态的展开系数，声场中的声压、质点法向速度等声学量都可由源强声辐射模态叠加得到。球形声源和棱台体声源的分析表明：源强声辐射模态保留了传统的声辐射模态优点，更方便解决复杂结构声辐射问题。