Thermal failure under conditions of restrained deformation

The time behaviour of solids during unsteady temperature conditions is cons idered. The conditions for the initiation of failure of a solid are formula ted in the form of conditions for the attainment of the threshold values of stress and strain fields. The evolution of a cracked region through the bo dy is considered. It is shown that the destruction process is divided into two stages in some cases. At the first stage, when a threshold value is ach ieved at some point or region of the body a jump-like extension of the regi on occurs until a state of equilibrium within the region is attained. This jump-like destruction can be considered as an instability process. Various examples are presented relating to the destruction of brittle solids. The i nfluences of plasticity and time-dependent characteristics is considered.