Cryogenic Compressive Strength and Thermal Deformation of Reinforced Polyurethane Foam Material for Membrane Type LNG Carrier

Abstract

LNG carrier is purposed to transport a liquefied LNG cargo which is reduced to 1/600 of volume in temperature condition of -163°C. In the context of structural performance on LNG cargo hold, the mechanical and thermal behaviors of insulation material under cryogenic temperature are considered as one of the critical factors for the hold design. This paper deals with the thermal deformation and the compressive strength of the reinforced polyurethane foam (RPUF) adapted for the insulation material of membrane type LNG carrier via both material tests and numerical simulations realizing the cryogenic condition. The material tests related to the thermal deformation are carried out to investigate the characteristics for thermal transfer on the actual RPUF specimen. The heat transfer simulations based on finite element analysis (FEA) are carried out using forced convection theory. The results of heat transfer analyses are compared to the material test results. Reasonable cryogenic conditions on RPUF are reviewed from both the analyses and the test results. In the regard of static material strength for the RPUF, the compressive material tests are carried out. The cryogenic temperature effect on the compressive strength of RPUF is evaluated by comparing to the room temperature material test results. From the compressive material tests, the effect of temperature on the ultimate compressive strength is investigated with variation of elongation.