Cross bore size and wall thickness effects on elastic pressurised thick cylinders

Three-dimensional finite element analyses were performed on closed-ended thick-walled cylinders with a radial cross bore under internal pressure. The aim of this study was to determine the behaviour of the hoop stress as well as to establish the optimal Stress Concentration Factors (SCF). Cylinders of thickness ratios of 3.0 down to 1.4 with cross bore size ratios (cross bore to main bore ratio) ranging from 0.1 to 1.0 were studied. The maximum hoop stress was found to increase with the increase in the cross bore size. Amongst the five different circular radial cross bore size ratios studied, the smallest cross bore size ratio of 0.1, gave the lowest hoop stress while the highest stress occurred with a cross bore size of 1.0. Moreover, the lowest SCF occurred in the smallest cross bore size ratio of 0.1 at a thickness ratio of 2.25 with a SCF magnitude of 2.836. This SCF magnitude indicated a reduction of pressure-carrying capacity of 64.7% in comparison to a similar plain cylinder without a cross bore.