Statistical estimation of extreme sloshing impact pressure and its validation based on dynamic behavior of insulation materials

Abstract

The design of an insulation material in a liquefied natural gas cargo containment system (LNG CCS) is mainly subjected to dominant sloshing impact loading. The sloshing impact loading, caused by the relative motion between the LNG carrier and the LNG CCS itself, continuously acts on the insulation material during the laden voyage. In the present study, impact tests were conducted on an insulation material consisting of polyurethane foam and plywood. The extreme sloshing impact energy had been set up after considering the sea conditions of wave height, wave period and a design life of 25 years of the LNG carrier. The extreme sloshing impact pressure was calculated using the statistical method of a generalized extreme value distribution (GEVD) combined with the Pierson–Moskowize spectrum and DNV code to obtain the period parameter of GEVD. GEVD was applied as the comparison of dynamic test results of insulation material based on force equilibrium. According to test results, significant sloshing impact pressure was verified as the dominant loading from test results of impact energy 31.66 J causing the overall plastic region of 0.144 mm mm−1.