Criterion for Failure of Internally Wall Thinned Pipe Under a CombinedPressure and Bending Moment

摘要

Failure criterion is a parameter to represent the resistance to failure of locally wall thinned pipe, and it depends on materialrncharacteristics, defect geometry, applied loading type, and failure mode. Therefore, accurate prediction of integrity of wallrnthinned pipe requires a failure criterion adequately reflected the characteristics of defect shape and loading in piping system.rnIn the present study, the finite element analysis was performed and the results were compared with those of pipe experimentrnto develop a sound criterion for failure of internally wall thinned pipe subjected to combined pressure and bending moment.rnBy comparing the predictions of failure with actual failure load and displacement, an appropriate criterion was investigated.rnFrom this investigation, it is concluded that true ultimate stress criterion is the most accurate to predict failure of wallrnthinned pipe under combined loads, but it is not conservative under some conditions. Engineering ultimate stress estimatesrnthe failure load and displacement reasonably for all conditions, although the predictions are less accurate compared with thernresults predicted by true ultimate stress criterion.