The strength and deformations of torispherical ends for glass-reinforced plastic pressure vessels—Part 2: Effect of torisphere geometry for ends of fixed head height

Abstract

Four further glass-reinforced plastic cylindrical pressure vessels with torispherical dished ends have been tested to destruction. Together with two vessels already reported on in Part 1 of this paper, these specimens form part of a group with the same head height of 0·25 m but with three different torus radii of 0·1 m, 0·146 m and 0·188 m, giving crown radii of 0·71 m, 0·8 m and 1·0 m, respectively (two vessels of each geometry were tested). As in Part 1, results from the tests were compared with those suggested by the current UK design code (BS 4994) and the predictions of a computer-based elastic stress analysis (BOSOR 4). In contrast to BS 4994, BOSOR 4 indicates that there is little difference in strength between dished ends with the two larger knuckle radii. A torus radius of 0·1 m, however, does produce a significant increase of maximum stress and strain. In fact, of the four additional vessels tested, only those two of this latter geometry ultimately failed in the dished end, those of knuckle radius 0·146 m rupturing in the cylinder.