A review of low-frequency vibration isolation in marine vessels and underwater vehicles using phononic crystal metastructures

Ship vibration and underwater noise from onboard machinery pose serious challenges to vessel safety, stealth, structural integrity and the protection of marine ecosystem. Existing isolation techniques are often ineffective in reducing the low-frequency vibrations, which are predominant in marine vessels. Recent developments in phononic crystals provide a promising approach by creating bandgaps that inhibit elastic and sound wave propagation. This review examines the application of phononic crystals, particularly locally resonant phononic crystal (LRPC) metastructures, for low-frequency vibration and noise control in marine vessels. It outlines the limitations of conventional isolation systems, fundamentals of phononic crystals, and design strategies adopted for implementation in marine vessels. Various types of resonators are discussed, highlighting their importance for integration into floating raft system, ship hulls, decks, etc. The challenges related to fabrication, optimization, and real-world implementation are identified, and future research directions are proposed to enhance their performance in marine applications.