Vibration isolation of LNG containment systems due to sloshing with glass fiber composite

Since the stainless steel primary barriers of Cryogenic Containment System (CCS) for Liquefied Natural Gas (LNG) ship failed by impact loads due to LNG cavitation during operation, the stiffness and strength of the primary barrier was increased much to endure the impact pressure of LNG, which increased the transfer of impact load to foam insulation panels under the primary barrier. The increase of impact load to the foam insulation panels will induce crack propagation into the insulation foam panels due to the low toughness of insulation foams at cryogenic temperatures.In this work, an impact isolation system was developed using glass fiber composite mats to lower the impact load transmission into the foam insulation panels. An optimal design process for the vibration isolation system was conducted by a numerical method. For reliability of the impact isolation system, cryogenic fatigue tests of the glass fiber composite mats were performed. Also, an impact test equipment with low impact duration was developed to simulate the efficiency of the impact isolation system.

► We suggest a vibration isolation layer (VIL) to reduce the impact transfer inside LNG ship. ► A glass fiber mat with polypropylene binder for VIL is durable under cryogenic impact. ► We analyze the impact reduction ratio by VIL by numerical analysis. ► We perform a impact test for VIL with the duration of impact of cavitation impact. ► VIL reduces the impact transfer to 20% compared to that without VIL.