No abstract

In this work a three-dimensional finite element study is carried out of pressurized piping tee (tee) intersections, with local area wall thinning (LTA). Two types of stress analysis are carried out, dealing respectively with the determination of the stress concentration factor (SCF), and of the plastic collapse load. Stress values determined for vessels with uniform thickness are compared with previously published work. An evaluation is then made of the effect on the SCF values of varying the size and shape of the LTA around the intersection. This is followed by a parametric study in which the SCF and the collapse load are computed for intersections with different depths of wall thinning. Finally, comments are made on the fatigue of tees with LTA having cyclical loading superimposed on the constant pressure loading.

A linear elastic finite element analysis (FEA) is carried out to determine the stress concentration factor (SCF) of a pressurized sphere-nozzle intersection. Nine-noded axi-symmetric 2D (ring) elements are used, and vessels without and with inner-wall local thinned areas (LTA) are considered. The SCF values obtained for vessels with uniform wall thickness are compared with previously published experimental and analytical results, and also with results from standard formulas given in the literature. An evaluation is made of the effect on the SCF of three types of inner-wall LTA; thinning in the nozzle, in the sphere, and in both components. As well, an evaluation is made of the effect on the SCF of growth of the LTA away from the intersection. A detailed parametric study is then carried out to determine the SCF for vessels with different depths of LTA. An elastic-plastic fatigue analysis for simulated seismic action is next carried out for some sample intersections, without and with LTA. The results provided are intended to contribute to the information available on the stress and fatigue characteristics of sphere-nozzle intersections with LTA.

No abstract

No abstract