VALIDITY OF PROCEDURE FOR PLASTIC COLLAPSE ASSESSMENT OF A LOCAL THIN AREA NEAR VESSEL AND NOZZLE INTERSECTIONS SUBJECTED TO INTERNAL PRESSURE AND EXTERNAL LOADINGS

There are numerous cases in which a volumetric flaw such as a local thin area (LTA) is found in pressure equipment such as vessels, piping, tanks, and so on. Sometimes it is found near vessel and nozzle intersection. A fitness for service (FFS) rule of such cases was desired, because plastic collapse assessment of LTA near vessel and nozzle intersection usually needed to conduct by numerical analysis such as FEA. Recently, an FFS assessment rule of plastic collapse assessment of LTA near vessel (run-pipe) and nozzle (branch pipe) intersection subjected to internal pressure and external loadings has been developed and proposed by one of authors of this paper. In this paper, the proposed plastic collapse assessment rule was verified with results of experiments and FEA for cylindrical vessels with an LTA near vessel and nozzle intersections subjected to internal pressure and external loadings.