集中系モデルによる音響振動連成現象の解析

抄録

Suppression of noise and vibration in machine products is an important problem, and many methods have been studied. In particular, structural-acoustic coupled effects due to the weight reduction of machines cannot be ignored. Therefore, research on efficient analysis methods for coupled systems is required. In structural-acoustic coupled analysis, the finite element method (FEM) that the acoustic space is described by sound pressure and the structure is described by displacement is often used. In this method, eigenvalue analysis requires a long computational time because the mass and stiffness matrices are asymmetric. In our previous study, we proposed a concentrated mass model (CMM) of quadrilateral elements for two-dimensional acoustic space. This model consists of mass points and connecting springs, and has variable displacement in its acoustic space. Since the CMM has symmetrical mass and stiffness matrices, structural-acoustic coupled analysis can be performed efficiently. The effectiveness of the CMM was shown in the past for an acoustic space-membrane vibration coupled system. In this paper, we propose the CMM of arbitrary element shape in structural-acoustic coupled analysis. Furthermore, we propose a coordinate transformation method to improve calculation speed by reducing the degree of freedom while preserving the symmetry of coefficient matrices. The effectiveness of the proposed method is confirmed by numerical calculation.