Shock performance analysis of high-static-low-dynamic stiffness floating raft vibration isolation system

Floating raft vibration isolation systems (FRVISs) using isolators with high-static-low-dynamic stiffness (HSLDS) characteristics exhibit excellent large-scale and multi-directional vibration attenuation performances and are well suited for stealth applications in ocean-going vessels. The shock isolation performances of the HSLDS-FRVISs under underwater explosion conditions are of great significance for the safe operation of machinery. However, our present state of understanding of this system is insufficient to facilitate the design of a more secure system. The present work addresses this issue by establishing an analytical model of an HSLDS-FRVIS with six degrees of freedom to facilitate detailed shock performance analyses. Two kinds of shock inputs are provided. The factors contributing to the HSLDS-FRVIS shock performance are analyzed by comparing the results obtained in different directions. The results demonstrate that the use of isolators with relatively small nonlinearities, large damping ratios, and proper installation locations is beneficial to the shock performance.