Progressive plastic deformation, or ratcheting, is a failure mechanism in ductile structures usually associated with non-proportional actions. In the case of cylindrical shell flat end connections, with or without opening, ratcheting may occur under the action of cyclically varying pressure from zero to a maximum value, i.e. for single action and, therefore, proportional loading. In this paper the ratcheting limits for this connection under this loading and for two different models are given, for an ideal-elastic ideal-plastic constitutive law, Mises' yield condition and associated flow law. The results are compared with each other and with the limits for global plastic deformation given in the literature. Copyright (C) 1996 Elsevier Science Ltd.