Sleeved cone-cylinder intersection under internal pressure

Conical shells feature commonly in pressure vessels and piping, for example as reducers and end closures. When a conical shell is joined to a cylindrical shell, a slope discontinuity is introduced in the shell meridian, leading to local high bending and circumferential membrane stresses when the shell is pressurized. The strength of cone-cylinder intersections is therefore a major concern for the designer. This paper presents an investigation into the collapse behavior and strength of cone large end-to-cylinder intersections with locally increased wall thickness (i.e., sleeving or sleeve reinforcement) under internal pressure. The study is aimed at developing a simple method for the estimation of the axisymmetric failure strength. Simple equations for the plastic limit loads are first developed based on small deflection elastic-plastic finite-element calculations. An approximate procedure for taking into account the beneficial effect of geometrical change is then suggested and briefly discussed. The strength equations established here are directly applicable in practical design and are suitable for future inclusion into pressure vessel codes.