含表面裂纹PE管道临界失稳压力的计算与分析

Calculation and Analysis of the Critical Buckling Pressure of PE Pipes with Surface Crack

针对PE管力学性能、缺陷尺寸及失效模式的不确定性,建立基于可靠性分析计算PE管临界失稳压力的方法。计算得到不同管材、标准尺寸比、失效模式、裂纹类型下,含表面裂纹PE管的临界失稳压力-管道裂纹深度与管道壁厚比曲线,分析各因素对该曲线的影响,为PE管的设计选材及安全评定提供指导。通过总结含表面裂纹PE管韧脆转化规律,为确定管道失效模式,防止管道脆性断裂提供理论依据。

Aiming at the uncertainty of mechanical properties, failure modes and defect size of polyethylene （PE） pipe, a new method to calculate critical buckling pressure of PE pipe was established. With differences of material, standard dimension ratio, failure mode and crack types, the critical buckling pressure-the crack depth and diameter ratio curves were obtained. The impacts of various factors on the curve were analyzed, which could provide guidance for the design of material selection and safety assessment of PE pipes. Though summarizing the rule of toughness-brittleness transition of PE pipes with surface crack, theoretical evidence was provided for definition of failure mode and prevention of brittle fracture of PE pipes.