Analysis on the vibration-acoustic coupling in cabins using a low dispersion meshless method

Analyzing the acoustic-structural coupling in airplane cabins is an important problem in the noise control and acoustic design. The wave-based methods, such as finite element method and classical meshless method, are commonly used in simulations of the acoustic-structural coupling in cabins. However, these methods usually suffer from the dispersion, which reduces the accuracy in mid-frequency range. Aiming at the problem, a low dispersion meshless model was developed, which is capable of reducing the distortion of the stiffness matrix. Firstly, a model for the acoustic-structural coupling under hybrid exciting sources was derived. Then, a smoothing technique for sound pressure gradients was developed based on the supporting domain of the meshless method. The technique can reduce the matrix stiffness of the coupling model. Lastly, a new stiffness matrix was reconstructed by combining the ones obtained by the classical meshless method and smoothing technique. The low dispersion meshless model has been used to simulate the acoustic-structural coupling of a rectangular enclosure and a practical cabin structure. The results were compared with those obtained by the finite element method, classical method and measurement. The comparisons demonstrate that the low dispersion meshless model has higher accuracy for simulating the system stiffness and gives closer results to real solutions in mid-frequency ranges.