Some considerations on failure of solids and liquids

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