표면 균열이 있는 천연가스 수송용 고장력 강관의 신뢰성 평가

초록

The demand in the natural gas has continuously been increasing in the world owing to the environmental problems and its high efficiency. The natural gas is usually transported to the end-users through the high strength pipeline. One of the notable problems for these pipelines is the brittle fracture initiated at various defects due to the extremely low temperature(-162℃) of the transported natural gas. It is, thus, required to evaluate the effect of the defect of pipeline in terms of the on economical and social losses. In this paper, the reliability of the high strength pipeline with a semi-elliptical crack along the surface is estimated. The failure probability is calculated by using the probabilistic methods, such as the FORM(First Order Reliability Method). The reliability analysis is conducted for the API 5L X65. Furthermore, the effects of probability distribution characteristics of random variables in LSF(Limit State Function) such as the normal distribution on the failure probability are systematically studied.