| Cylinder is a common element in constructing pressure vessels and pipes. The limit load of a defective cylinder is a very important input in a structural integrity assessment of a pressure vessel or pipe using R6 type procedure. Currently, limit load solutions for a thin-walled cylinder with a circumferential crack under combined loading are well developed. However, the limit load solutions for a thick-walled cylinder with circumferential cracks under combined internal pressure and other load types are still lacking. The purpose of this dissertation is to develop limit load solutions for a thick-walled cylinder with a fully circumferential crack under combined internal pressure and axial tension. The researches performed and corresponding results are as follows.(1) A limit load solution for a thick-walled defect-free cylinder under combined internal pressure and axial tension is derived based on the Mises yielding criterion, considering the effect of tri-axial stress distributions in the cylinder and the three dimensional geometry characteristics. The predictions using the new solution are compared with results of elastic-perfectly plastic finite element analyses for various ratios of outer/internal radii of the cylinders and loading ratios between tension force and internal pressure with very good agreement. The new solution is also compared with the results from others for selected cases and the results show that the solution obtained in this work is currently the best one.(2) The limit load solutions for a thick-walled cylinder containing a fully circumferential internal surface crack under combined internal pressure and axial tension are derived based on the Mises yielding criterion, considering the effect of tri-axial stress distributions and three dimensional geometry characteristics. Two cases, with/without crack face pressure, are considered. The predictions using the new... |
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