On Durability of Structurally Inhomogeneous Materials

Abstract

Numerical methods used to calculate strength are based on energy approaches and minimization of functionals of one type or another. Yet the model of a material is limited to stable processes of deformation. As a result, a considerable number of deformation properties related to realization of the softening stage in materials of structural elements remains unaccounted for. To describe fracture as a new phenomenon in the behavior of structures, one needs to apply newer experimental and calculational approaches. The article cites results of modelling and experimental notions on the stage of softening in materials and its role in determining their durability. It is proposed to define the durability of a structurally inhomogeneous material as its capacity of equilibrium deformation beyond its ultimate strength under specified loading conditions. That reflects nonlocality of criteria for the failure of the material, their dependence both on its own properties and the geometry of a structural element. Complete stress-strain diagrams for structural materials of various classes and examples on how the softening stage is realized in structural materials are given.