Plastic Collapse Assessment Procedure for Vessel With Local Thin Area Simultaneously Subjected to Internal Pressure and External Bending Moment

Abstract

Assessment of the local thin area should be undertaken for both tension and compression bending. In this paper, simplified reference stresses for a flaw in a cylinder are proposed. By using these results, a newly developed p-M (internal pressure ratio and external bending moment ratio) diagram which can evaluate the collapse condition for pressure equipment such as vessels, piping, and storage tanks with a local thin area simultaneously subjected to internal pressure p and external bending moment M due to earthquake, etc., is proposed. The p-M line is verified by comparison with the finite element analysis results and the numerous results of experiment for a cylinder with a volumetric flaw obtained through the reference literatures. It was clarified that the differences in collapse limit between the p-M line and DNV guideline under both internal pressure and compression moment became evident where the outer diameter/wall thickness of a cylinder is large and the yield ratio of the material is small.

Limit state equation and failure pressure prediction model of pipeline with complex loading

“…Shuai et al 40 applied finite element analysis to investigate the buckling bearing capacity of pipelines under axial compressive loading and internal pressure. Konosu and Mukaimachi 41 put forward a plastic collapse assessment procedure for pressurized vessels with bending moments. Mohd et al 42 investigated the same pipeline case.…”

Study on Sufficiency of Reference Stress Solutions for Crack-Like Flaws for Fitness-for-Service Evaluation

“…Reference stress represents the margin of the admissible stress state in the ligament against plastic collapse for cracked bodies in the unit of stress , and is given as a function of structure, crack size and shape, membrane stress (or axial load, internal pressure), and bending stress (or bending moment). In HPIS Z101-2, reference stress solutions derived from appropriate technical bases have been adopted based on the past studies [2][3][4], and the adequacy has been verified [5].…”