A Model Estimating the Propagation Behavior of through cracks in Aluminum alloy A5083-O for LNG Tank

J. Ocean Eng. Technol. 1998;12(1):50-57.

LNG탱크용 알루미늄합금 A5083-O의 관통균열 전파거동 예측 모델

김영식,조상명,김종호

한국해양대학교 재료공학부,부경대학교 생산가공학과,한국해양대학교 기관공학부

Keywords: LNG, LBB, Fatigue Fracture, Fracture toughness, Through crack, Secondary barrier

핵심용어: 액화천연가스, 파단 전 누실, 피로파괴, 파괴인성, 관통균열, 2차 방벽

Abstract

The leak before break(LBB) concept is generalized on the design of LNG tanks, pressure vessels and nuclear reactor in that any leakage of containment, in whatever amount, will not result in catastropic failure. For this purpose it is necessary to determine the surface crack shape, the opening displacement and the risk of catastropic brittle fracture when it becomes a through crack. In this study the crack propagation behavior of surface flaws and the crack opening displacement of through cracks under combined membrane and bending stresses were investigated with fatigue tests and fracture toughness test of aluminium alloy A5083-O. And fracture mechanics analysis of the crack opening displacement of through cracks were made in order to develop a new model expressing the behaviors of COD under combined membrane and bending stresses.