Effect of temperature on the mechanical performance of plywood used in membrane-type LNG carrier insulation systems

Abstract

In this study, the mechanical performance of melamine-urea-formaldehyde (MUF) resin plywood composed of an orthotropic material, which is used as a structural material in liquefied natural gas (LNG) cargo containment systems (CCSs), is evaluated. With a decrease in temperature, the plywood changes from ductile to brittle under compressive loads; thus, it may fail to distribute the compressive loads caused by sloshing impact as well as lose its stiffness, which helps maintain the shape of the structure. However, only a few studies investigated the mechanical characteristics of MUF resin plywood under compressive loads caused by sloshing impact as well as the crack propagation and change in material features with decreasing temperatures. Therefore, the present study investigated the mechanical performance of MUF plywoods of different thicknesses under different temperatures and grain orientation parameters. The results indicate the mechanical properties of MUF plywood for compression with decreasing temperatures. Furthermore, based on thermomechanical analysis, this study shows that the critical temperature at which the plywood material tends to transition from ductile to brittle behavior is − 110 °C. This finding will help in the design of MUF plywood-based LNG CCSs considering its low-temperature brittleness.

Effect of ultra-low temperature on some mechanical properties of painted and film-coated plywood

“…As a result of cooling from +40 to -40 °C, the BS and MOE values increased by 34 % and 38 %, respectively. Cha et al (2020) found that the MOE of plywood increased with decreasing temperature. Zhao et al (2015) studied the MOE of water-saturated, fresh-cut, air-dried, and oven-dried birch (Betula platyphylla) wood under the temperatures at +20 °C and -196 °C.…”

“…Mechanical properties such as bending strength (Kim et al 2015, Kim et al 2018, modulus of elasticity (Kim et al 2015, Kim et al 2018, tensile strength (Kim et al 2015) and compression strength (Cha et al 2020) have been found to increase during freezing in plywood made of the MUF and PF resins. Similarly, it has been discovered that compression strength and bending strength values increased in wood composites with decreasing temperatures (Ayrilmis et al 2010, Bekhta andMarutzky 2007).…”

“…Plywood has recently, become popular in ultra-cold conditions, such as liquid natural gas (LNG) cargo ships (Cha et al 2020, Kim et al 2015, Kim et al 2018. Even though previous studies have focused on the effects of ultra-low temperature on BS, MOE and compressive strength on plywood, there is no study on tensile shear strength at ultra-low temperature for plywood.…”