Plastic collapse behaviour and strength of cone-cylinder and cone-cone intersections

Cone-cylinder and cone-cone intersections with or without ring stiffeners are common features in pressure vessels, piping components and other industrial shell structures. Under internal or external pressure, these intersections are subject to high circumferential membrane stresses as well as high bending stresses due to the presence of a slope discontinuity. As a result, they are susceptible to local plastic collapse. This paper presents a summary of a number of recent investigations into the plastic collapse behaviour and strength of cone-cylinder and cone-cone intersections. The aims of the paper are to clarify several aspects of the plastic collapse behaviour of these intersections, and to introduce a number of simple plastic collapse strength formulas suitable for inclusion in future pressure vessel codes in a plastic design-by-analysis approach.