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Friday, 21 October 2016
Effects of cryogenic thermal cycle and immersion on the mechanical characteristics of phenol-resin bonded plywood
Published Date December 2015, Vol.72:90–102,doi:10.1016/j.cryogenics.2015.09.007 Author
Jeong-Hyeon Kim a
Doo-Hwan Park a
Chi-Seung Lee a
Kwang-Jun Park b
Jae-Myung Lee a,,
aDepartment of Naval Architecture and Ocean Engineering, Pusan National University, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735, Republic of Korea
bGas Technology R&D Group, Daewoo Shipbuilding & Marine Engineering, 26, Eulji-ro 5-gil, Jung-gu, Seoul 110-210, Republic of Korea
Received 28 May 2015. Revised 17 September 2015. Accepted 26 September 2015. Available online 3 October 2015. Highlights
Cryogenic mechanical properties of phenolic-resin plywood were investigated.
Influences of cryogenic thermal loads on plywood adopted in an LNG CCS were investigated.
Fracture patterns of phenolic-resin plywood depending on grain orientation were discussed.
Performance degradation owing to the cryogenic thermal cycle and immersion was observed and discussed.
Abstract The main objective of the present study is to investigate the performance degradation of the plywood used in a liquefied natural gas (LNG) cargo containment system (CCS). A plywood sheet features an odd number of thinly layered wooden plies bonded perpendicularly to the previous layer to give it a very strong and durable structure. Owing to this strong point, plywood is applied to a variety of interior and exterior applications. Above all, it is widely adopted as insulation panels in an LNG CCS owing to a high stiffness with low density and its superior mechanical capabilities. As an insulation material of an LNG CCS, plywood is constantly exposed to repeated wave-induced thermal variations caused by the loading (−163 °C) and unloading (20 °C) of LNG during general operating periods of 25 years on average. Therefore, the effects of cryogenic-level thermal loads on the material characteristics of plywood must be analyzed with respect to the design and safety aspects of LNG CCSs. In the present study, the influences of the estimated thermal load, testing temperature, and grain orientation on plywood adopted in an LNG CCS are investigated. In terms of safety and design, the repeated thermal loads in a LNG CCS must be considered because the modulus of elasticity (MOE), tensile strength (TS), and modulus of rupture (MOR) are degraded by thermal treatments, such as cyclic thermal-shock and cryogenic immersion. Keywords