A unified stress-based approach to assess failure in solids and liquids

Failure in continuum media, either solids or liquids, can be regarded as a physical phenomenon which mathematically can be identified by the fulfilment of a limit condition usually involving the stress state inside the material. By considering classical failure theories for solids (plasticity and fracture mechanics approach) and a recent theory on the rupture (cavitation) for liquids, common peculiarities of the failure conditions for both classes of materials are presented. Finally, by introducing a stress field parameter, the stress triaxiality t, which can be used to identify the limit condition of collapse for both classes of the considered materials, some unified considerations on failure of solids and liquids are made. It is shown that the collapse functions for both classes of continuum materials present a similar form.