含环向穿透裂纹海底油气管道的安全评估

采用BS7910评定方法对给定载荷条件下的管道焊接接头焊趾处的穿透裂纹进行评定,探讨了穿透裂纹尺寸变化对焊接接头安全评定的影响.通过一种含环向穿透裂纹管道在纯弯曲载荷下的LBB.ENG2 J积分估算方法,采用Matlab编程计算含环向穿透裂纹管道的J积分值.计算结果表明,穿透裂纹半角不大于π/6时,其对应的评定点均落在BS7910的3C级评定曲线定义的范围内,这说明含有该范围内裂纹的缺陷是可以验收的,从而验证了含环向穿透裂纹管道的LBB.ENG2 J估算方法适于在工程实际中推广应用.

Safe assessment of circumferential through-wall crack in pipeline

According to the results of the BS7910 assessment,the through-wall crack at the toe of a weld in pipeline under given load was carried out.The influence of the crack size change on the weld safe assessment is discussed.Through a J integral estimation scheme(LBB.ENG2)for pipeline with circumferential through-wall cracks under pure bending,J integrals of pipeline which has circumferential through-wall cracks are computed using Matlab programming.The assessment results indicate that the assessment points are within the region defined on the failure assessment diagrams using Level 3C.Therefore,the structure containing definite crack can be accepted.The results show that LBB.ENG2 J integral assessment scheme of circumferential through-wall cracks can be applied in engineering.