Vibro-acoustic behavior of partially submerged composite sandwich plates with negative Poisson's ratio grids

Composite sandwich structures demonstrate significant potential for applications in Marine structures due to their corrosion resistance, high specific strength, and lightweight characteristics. This paper explores the underwater vibro-acoustic characteristics of composite sandwich plates featuring negative Poisson's ratio grids. The composite sandwich plate comprises orthotropic carbon fiber and glass fiber laminates, along with a periodic grating structure. The fundamental units of the grating structure are star grids, chiral grids, and concave hexagonal grids, respectively. The vibration and noise reduction performance of the negative Poisson ratio composite sandwich plate is affirmed through comparison with the traditional regular hexagonal composite sandwich plate. The chiral and concave hexagonal grids demonstrate outstanding noise reduction capabilities, achieving up to 25 dB, though their vibration damping performance is poor. In contrast, the star grid still exhibits high acoustic response peaks but maintains a relatively stable vibration damping performance of around 5 dB. Finally, the paper explores the effects of different parameters on the vibro-acoustic behavior of composite sandwich plates with negative Poisson ratio grids, including cell equivalent Poisson ratio, panel layup angle, and plate curvature.