Research on root morphology regularization method of incomplete penetration defect in pressure pipe

Incomplete penetration defect is one of the most common welding defect generated in field welding process, this defect has become a potential threat to the safety operation of pressure pipe. Scientific and rational regularization method for incomplete penetration defect is the important basis of the safety assessment for pipe. According to actual root morphology of incomplete penetration defect, four regularized notch shapes, which were elliptical concave notch, round concave notch, round convex notch and flat notch were obtained by simplification in this paper. Then the effect rules of notch width, depth and notch root curvature radius on plastic failure load were studied by the results of nonlinear finite element analysis. Finally, the plastic failure load of pipes with four different regularized notch shape were gained by analyzing, and then the regularization treatment method of incomplete penetration defect based on minimum plastic failure load principle was proposed.