Abstract: The finite element method based acoustic-structural coupled models are generally limited to low frequency problems due to the numerical dispersion error. In order to solve this problem, an accurate and efficient acoustic-structural coupling scheme based on the gradient-weighted finite element method (GW-FEM) for acoustic fluid field and central-point discrete shear gap method (CPDSG) for the shell structure has been developed, namely, GW/CPDSG. Reconstructing the acoustic pressure gradient field using the GW-FEM and shear strain field of the shell element using the CPDSG, the coupled system equation is finally obtained through the compatibility and equilibrium conditions on the coupled interface. The coupled model has been applied to analysis the frequency response of a practical vehicle acoustic-structure coupling system, the numerical results demonstrate that the GW/CPDSG method achieves higher accuracy than the finite element based coupling method for low and medium frequency acoustic-structure coupling problems, especially for complex acoustic-structure coupling systems. The GW/CPDSG shows good adaptability and reliability for complex systems, which can significantly raise the upper limit of the analyzable frequency and reduce the computational cost for large scale problems. Thus, the GW/CPDSG is very promising in analyzing acoustic-structural coupling responses for practical engineering problems.

Key words: acoustic, shell structure, acoustic-structure interaction, the central point-based discrete shear gap method, the gradient-weighted finite element method