A Prediction of Crack Propagation Rate under Random Loading

J. Ocean Eng. Technol. 1994;8(2):115-123.

랜덤하중에서의 균열전파속도 추정법에 관한 연구

표동근,안태환

홍익대학교 공과대학,충주산업대학교

Keywords: Random Loading, Storm Loading, Crack propagation Rate, Effective Stress Intensity Factor, Crack Closure

핵심용어: 랜덤하중, 파도하중, 균열전파속도, 유효응력확대계수, 균열닫힘

Abstract

Under variable amplitude loading conditions, retardation or accelerated condition of fatigue crack growth occurs with every cycle, Because fatigue crack growth behavior varied depend on load time history. The modeling of stress amplitude with storm loading acted to ships and offshore structures applied this paper. The crack closure behavior examine by recording the variation in load-strain relationship. By taking process mentioned above, fatigue crack growth rate, crack length, stress intensity factor, and crack closure stress intensity factor were obtained from the stress cycles of each type of storm ; A(6m), B(7m), C(8m), D(9m), E(11m) and F(15m) which was wave height. It showed that the good agreement with between the experiment results and simulation of storm loads. So this estimated method of crack propagtion rate gives a good criterion for the safe design of vessels and marine structure.