Cryogenic impact resistance of chopped fiber reinforced polyurethane foam

Abstract

Liquefied natural gas (LNG) is primarily carried by a membrane type LNG ship, which has a cryogenic containment system composed of dual tightness barriers and insulation boards. The insulation board should have cryogenic reliability as well as high thermal insulation for the safe and efficient transportation. Sandwich construction and fiber reinforced polyurethane foam (PUF) are generally used for the insulation board and the core materials, respectively. During the operation of the LNG ship, cavitation and sloshing could generate an impact load on the PUF, which is an ongoing concern in the ship building industry. Therefore, the cryogenic impact resistance of the chopped E-glass fiber reinforced PUF was investigated with respect to the amount of chopped fibers. The drop weight impact test was conducted at a cryogenic temperature of -196 degrees C using liquid nitrogen. The applied maximum impact pressure, permanent strain and damage factor were measured to assess the damage caused by the impact test, from which the critical impact energy was investigated. From the experimental results, a criterion was suggested to assess the cryogenic impact resistance of the PUF and it was determined that the chopped fiber reinforcement significantly increased the impact resistance of the PUF at the cryogenic temperature.