Sloshing impact loads have been reported repeatedly throughout the lifetime of the ship. However, a study on the mechanical performance of polyurethane foam with repetitive impact load has not been conducted despite the necessity of evaluation. Therefore, in this study, the effect of repetitive impact loading on mechanical behavior of LNG insulation panel was investigated. To do this, a series of drop impact test was performed on two types of LNG insulation panels with polyurethane foam and glass fiber reinforced polyurethane foam. After the impact test, evaluation of cryogenic mechanical behavior was conducted.
As the global demand for liquefied natural gas to pursue clean energy increases, the capacity of the LNG carrier is increasing, which can cause serious damage on the membrane insulation system. Sloshing is a violent resonance motion of a free surface inside a moving CCS. Moving liquid will force the containment system wall. Severe and violent sloshing typically occurs when the vessel moves with motion periods close to the highest sloshing resonance period for the liquid in the cargo. Failure of LNG CCS can lead to massive loss of human and material resources, so robust design and production of LNG CCS is essential. In this reason, various types of insulation systems have been proposed to store LNG. The structures consist of a primary barrier of metallic material to prevent leakage of cryogenic fluids and a composite material insulation panel to control the vaporization due to the temperature rise. Insulation panel is made of plywood and polyurethane foam as main materials and also undergoes fluid impact such as sloshing. Polymeric foam such as polyurethane foam (PUF) and glass reinforced polyurethane foam (RPUF) has been widely employed as insulator in industry because of its low thermal conductivity, low permeability and light weigh. Furthermore, the volume of polymeric foam does no change due to temperature gradient. PUF is fabricated from the isocyanates and polyols which RPUF is the mixture of high density polyurethane foam and chopped glass fiber.
