Low frequency ship vibration isolation using the band gap concept of sandwich plate-type elastic metastructures

Elastic metamaterial is a type of artificial composite material/structure with unique subwavelength physics property, which shows attractive potential application in low-frequency sound and vibration control. In this paper, a ship vibration isolation method using the band gap concept of sandwich plate-type elastic metastructures is proposed to solve the low frequency vibration and noise control of marine power system. The flexural wave propagation and low-frequency vibration isolation characteristics of sandwich plate-type elastic metamaterials are investigated by using the finite element method combination with Solid-Shell multi-physics coupling model and Bloch theory. Numerical results demonstrate that the proposed sandwich plate-type elastic metastructures possess significant low-frequency subwavelength flexural wave band-gap and vibration isolation characteristics under the premise of structural strength and stiffness. The formation mechanism of flexural band gap is mainly attributed to the mode coupling of the local resonant mode and the Lamb wave mode of sandwich plate. The experimental measurements of flexural vibration transmission spectra were conducted to validate the accuracy and reliability of the numerical calculation method. In addition, the influences of geometrical parameters on the flexural wave band gap are studied. On this basis, the potential application of the proposed ship vibration isolation method in the marine power system is explored.