压力管道“先漏后破”评定的准则研究

Based on the elasto-plastio fracture mechanics, this paper established the expression formulas of limit buckling pressure P(subscript c) on the ligament of axial and circumferential surface cracks and the initial pressure for the through cracks P(subscript c). A new Leak Before Break (LBB) assessment criterion was put forward to predict the failure mode of pressure pipes, i.e., when P(subscript u) is less than P(subscript u) the pipe will leak; when P(subscript u) is equal to or larger than P(subscript c), the pipe will break, which is verified by the test data reported in literatures.