Sufficient discrete–integral criterion of rupture strength

The behavior of the atomic structure in the vicinity of the crack tip is modeled. The loss of stability and postcritical deformation of a triatomic cell in a close–packed atomic layer in tension are studied. For macrocracks in single crystals, the concept of the generalized Burgers vector is introduced. A sufficient discrete–integral strength criterion is proposed for normal–rupture cracks in the case where the stress fields have a singular component. In accordance with Novozhilov's hybrid model, this criterion is formulated with the use of a new class of solutions that differs from solutions used in formulating the classical sufficient strength criterion. In the limiting case where the energy characteristics of the postcritical deformation of the cell can be ignored, the sufficient criterion proposed admits a limiting passage to the necessary criterion. The critical loads calculated by means of the sufficient criterion differ substantially from those determined with the use of the necessary criterion; this makes it possible to describe the Rehbinder effect.