Analysis of the Compressive Behavior of Plywood Under Seawater and Cryogenic Temperature Effects

The global demand for liquefied natural gas (LNG) has led to a significant increase in the number of LNG carriers (LNGCs), consequently elevating the risk of operational accidents. Unlike conventional vessels, LNGCs present a high risk of fire and explosion and involve extensive repair times and costs due to the complex structure of the cargo containment system (CCS). This study investigates the effects of seawater exposure on the uni-axial compressive properties of plywood used in LNGC CCS structures, with the goal of establishing material strength criteria that could reduce repair requirements. The analysis focuses on the NO96 CCS, which incorporates the highest volume of plywood among existing designs. In this configuration, compressive strength is a critical design parameter. Therefore, the mechanical response of plywood was evaluated under both room temperature and cryogenic conditions (-163 °C), simulating the LNG operating environment. The results demonstrate that plywood exhibited increased compressive strength after three hours of seawater and saltwater immersion, although the rate of improvement diminished with extended exposure. In contrast, specimens immersed in distilled water showed a consistent reduction in compressive strength. Furthermore, cryogenic temperatures significantly enhanced the compressive strength compared to ambient conditions. This study establishes a methodology for assessing the mechanical performance of plywood under marine and cryogenic conditions, contributing to its reliable application in LNG carrier structures.