A phononic crystal suspension for vibration isolation of acoustic loads in underwater gliders

Currently, it is a common practice to apply underwater gliders with acoustic loads for hydroacoustic detection, but the self-noise of the vehicle inevitably interferes with signal acquisition. In this study, a novel suspension is designed based on phononic crystals to realize vibration isolation of the acoustic loads in underwater gliders. The vibration properties of finite-period phononic crystals with different layouts of unit cells are studied by analyzing the attenuation zones, and the three-period phononic crystal with prolonged metal ends is determined to be the optimal structure of the suspension. Moreover, the effect of physical parameters on the underwater attenuation zones of the proposed suspension is further investigated through acoustic-structure coupling, resulting in the formation of a design scheme for the suspension. A vibration test is performed in an anechoic pool, which reveals that the phononic crystal suspension has a stable vibration isolation effect at 120–5000 Hz and achieves a maximum vibration isolation of about 7 dB compared with the original structure. The results in the present work provide a theoretical reference for applying phononic crystals for vibration isolation in underwater vehicles.