Defects significantly affect the carrying capacity of pipe elbows. Accurately estimating the capacity permits fewer pipe inspections and replacements, saving time and reducing costs. To study the effect of defects, a 90° pipe elbow model with a 1016 mm-diameter and 19.9 mm wall thickness was built. The material is API X80 steel and the curvature radius is 6D. The plastic failure criterion and twice elastic slope method were adopted to determine the limit internal pressure load. Using the commercial finite element software, Abaqus, the influences of defect location, defect depth, defect length, defect width and pipe wall thickness on the ultimate bearing capacity of an pipe elbow with ellipsoidal pits was studied. Through multiple nonlinear regression analysis and nonlinear fitting, formulas for calculating the ultimate internal pressure load of large-diameter elbows with defects under various influencing factors were obtained. The formulas can provide guidance and reference for evaluating the residual strength of large-diameter elbows with defects.

缺陷会严重影响弯头的承载能力。准确估算容量可以减少对管道的检查和更换，节省时间并降低成本。为了研究缺陷的影响，建立了直径为1016毫米，壁厚为19.9毫米的90°弯管模型。材料为API X80钢，曲率半径为6D。采用塑性破坏准则和二次弹性斜率法确定极限内压载荷。利用商业有限元软件Abaqus，研究了缺陷位置，缺陷深度，缺陷长度，缺陷宽度和管壁厚度对带有椭圆形凹坑的弯头的极限承载力的影响。通过多重非线性回归分析和非线性拟合，得出了在各种影响因素下具有缺陷的大直径弯头的极限内压载荷的计算公式。该公式可为评估带缺陷大直径弯头的残余强度提供指导和参考。