Structural-Acoustic Coupled Analysis by Concentrated Mass Model

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 of coupled systems is required. Finite element method (FEM) is often used in structural-acoustic coupled analysis. In this method, the state of acoustic space is represented by sound pressure, and the state of structure is represented by displacement. However, eigenvalue analysis requires a long computational time because the mass and stiffness matrices are asymmetric. In this paper, we propose the concentrated mass model (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. Finally, typical element shapes are set for numerical simulation. Eigenvalue analysis is performed to confirm the effectiveness of the proposed method.