Numerical analysis of cylinders containing circular offset cross-bores

Boundary element analysis of thick-walled spherical vessels with surface cracks

“…However, if the size of the radial crossbore in the cylinder is relatively small (R s /Ri < 0.05), then a rise in hoop stress near the exterior surface can be seen, as demonstrated by the findings of Comlekci et al (2007). Similar trends to those in the present work can also occur in a cylinder if the crossbore is offset, or of the elliptical form (Masu (1997 and1998)). Also unforeseen, the variations of the circumferential stress factor for the larger crossbores…”

Offsetting of Circular Cross Bore Effects on Elastic Pressurized Thick Cylinders

“…The exact location ratios investigated included 0, 0.12, 0.24, 0.36, 0.48, 0.58, 0.685, 0.79 and 0.9. The offset ratio of 0.48 and 0.9 were similar to those studied by Masu [5] and Cole et al [10]. Whereas, the other offset ratios were chosen arbitrarily at the mid location to investigate the stress behaviour at those points.…”

“…Drilling of cross bores in the wall of the vessel introduce geometric discontinuities that alter the uniform stress distribution [5].Subsequently, these geometric discontinuities act as stress raisers, which create regions of high stress concentration especially along the cross bore depth. Nonetheless, high magnitudes of stress concentration are associated with persistent problems in the design of pressure vessels such as fractures, fatigue and local yielding [7].It is, therefore, necessary to design for an optimal minimum hoop stress concentration in order to reduce the occurrence of these problems.…”

“…Masu [5] investigated the effects of offsetting small circular cross bores in thick walled cylinder with a thickness ratio of 2, using finite element method. SCF reductions of 17 % and 42% were reported, when the cross bore was positioned in an offset ratio of 0.24 and 0.9, respectively, from the radial line.…”

“…Holes or openings are made in the wall of plain pressure vessels [5] to give provision for fitting essential operation and maintenance accessories. These accessories include relief and safety valves, bursting discs, gas inlets, flow circuit meters, temperature and internal pressure measurement, inspection covers and lubrication [2].…”