A plastic collapse mechanism for cylinders under uniaxial end compression

Abstract Tests performed on ring stiffened steel cylinders, of geometries used in offshore structures, and subject to axial compressive loading have shown that failure can occur in the vicinity of the end supports or the stiffener with the formation of an axisymmetric plastic bulge. The axisymmetric post-failure responses is studied in this paper by modelling the collapse mode by a rigid plastic mechanism. The results of the plastic mechanism approach and the assumptions on which it is based are compared to the behaviour of the cylinder predicted by a large deflection elasto-plastic finite element program; good agreement is found between the two. Experimental observations also compare well with the rigid plastic mechanism theoretical results.