钢悬链线立管环焊缝ECA断裂疲劳评估技术

ECA Fracture Fatigue Assessment Technology for Girth Weld of Steel Catenary Riser

为解决钢悬链线立管(Steel Catenary Riser,SCR)在深水服役过程中受波浪等循环载荷的作用容易产生疲劳失效的问题,依据英国标准BS 7910,运用Crackwise软件,对含有缺陷的SCR环焊缝进行工程临界评估(Engineering Critical Assessment,ECA),得到SCR着泥段和悬挂段两个关键区域的缺陷允许尺寸,并分析缺陷允许尺寸对错边和角变形的敏感性。结果表明:在外表面、内表面和埋藏等3类缺陷中,外表面缺陷最为危险,埋藏缺陷的临界尺寸随着缺陷与外表面距离的增大而增大;SCR悬挂段所允许的缺陷尺寸比着泥段小很多;角变形对缺陷允许尺寸的影响比错边的影响大。

In order to solve the problem that Steel Catenary Riser(SCR)is prone to fatigue failure due to cyclic loads such as waves during service in deep water,the Engineering Critical Assessment(ECA)of SCR girth weld with defects is carried out based on British Standard BS 7910 and Crackwise software.The allowable size of defects in two key areas of SCR,namely the mud section and suspension section,is obtained,and the sensitivity of allowable size of defects to edge offset and angular deformation is analyzed.The results show that:the outer surface defects are the most dangerous among outer surface,inner surface and buried surface defects,and the critical size of the buried defects increases with the distance between the defects and the outer surface;the allowable size of the defects of the SCR suspension section is much smaller than that of the mud section;and the influence of the angular deformation on the allowable size of the defects is greater than that of the edge offset.