A strain energy criterion for failure of floating ice sheets

Abstract

A failure criterion for floating ice sheets under stationary loads is presented, based on the concept of strain energy per unit volume and the results of some 40 prototype loading tests. The practical requirement for a time-independent failure criterion for ice, which is a viscoelastic material and thus subject to creep, is noted. Existing failure criteria are reviewed and shown to be unable to handle many practical situations. Subsequently, the concept of strain energy per unit volume is formulated and shown to provide a satisfactory failure criterion under varied loading histories. Analysis of the test results indicated the existence of a distinct instant marking the onset of failure of a loaded ice sheet. Because the behaviour of a loaded ice sheet between this instant and the final breakthrough of the load is partially random, it is suggested that the former be used as the practical limit of safety.