AN ESTIMATION TO PLASTIC LIMIT LOAD OF CRACKED EQUAL-DIAMETER WELDED PIPING BRANCH JUNCTIONS UNDER INTERNAL PRESSURE

摘要

In this work, an engineering analysis approach for plastic limit load of welded piping tees, by the relationship of internal force between run and branch pipe around the intersection, is presented. The approach is built on the following process: Firstly, an equation between the limit load and internal force of branch pipe surrounding the intersection is found based on the force equilibrium condition. Secondly, regarding this internal force as external force acting on the intersection of the run pipe, the approximate solutions of internal force around the intersection on run pipe, under the plastic limit load, can be given. Finally, referring to the von-Mises yield criterion, the plastic limit load of two intersecting cylindrical shells is obtained. By using this approach, an approximate plastic limit load solution of welded equal-diameter piping tees, which have circumferential crack in flank range surrounding intersection, is obtained under internal pressure. The solution is validated by finite element analysis.