Reference stress approach for failure strength estimates of a pipe with local wall thinning

This paper proposes a method based on the reference stress approach to estimate residual strength of a pipe with local wall thinning. The method is based on the equivalent stress averaged over the minimum ligament in the locally wall thinned region. Inspired by the reference stress method for approximate creep stress analysis, approximate estimation equations for the equivalent stress in the minimum ligament are proposed, which are then calibrated using detailed elastic-plastic 3-D FE analysis. The resulting estimation equations are found to be insensitive not only to pipe and defect geometries but also to material. Comparison of failure loads, predicted according to the proposed method, with published test data for corroded pipes shows excellent agreement.