Residual Stress in Predicted Failure Pressure Calculation

摘要

Editor's note: This article on residual stress and predicted failure on pressure calculation is being presented in two parts, with the second installation appearing in PGJ's September issue.(PGJ) - Pipeline safety regulations require performing a calculation of the predicted failure pressure (PFP) of defects as part of an engineering critical assessment. Whether to include residual stress from pipe manufacturing, and selecting the magnitude of residual stress, can significantly affect the outcome of the PFP calculation. Guidance for accounting for residual stress is inconsistent. A survey was performed of several dozen research reports describing testing and analyses of residual stresses induced by the pipe manufacturing process for various types of line pipe. A simple method for determining whether to account for residual stress, and if so, at what magnitude, has been devised for various categories of electric resistance weld (ERW) pipe, and also for non-ERW pipe.