Option of structural-analytical mesomechanics for bodies with stress concentrators

The developed approach takes into account the multi-level and multi-stage nature of destruction. The appearance of microcracks is necessarily preceded by the formation of zones of structural concentrators with a critical defective structure, which is characterized using diagnostic parameters of the magnetic memory method in the form of corresponding invariants of the magnetic distortion tensor. These diagnostic parameters along with the field of effective stresses, make it possible to simulate the formation of structural (micro and meso) cracks. The cracks create structural damage that can, under certain conditions, grow further. When such a property acquires a large number of structural cracks, there are prerequisites for macroscopic destruction, which will occur if only the body is sufficiently damaged. The proposed structural and analytical approach allowed us to create a flexible system of fracture criteria, to apply a multi-model analysis to the problems of destruction under a macro-inhomogeneous stress state or a complex stress state. A distinctive feature of the existing criteria in the proposed approach is that it was possible to take into account the factor of influence of zones of structural stress concentrators and their development on the destruction of specific materials. The fact that it is possible to perform strength diagnostics in a specific place of a real product with such an approach is of particular value. An important result of the work is the introduction of new characteristics of the magnetomechanical effect, that is the magnetic distortion and vector-intensity tensor, which characterize the non-uniform distribution of the self magnet field diffusing and allow the formulation of fracture criteria to take into account the influence of zones of structural concentrators of real materials. On the basis of the development of structural and analytical mesomechanics methods, taking into account the influence of structural and macroscopic stress concentrators on the nucleation and development of plastic deformations and damageability of the material, fracture criteria are formulated for bodies containing geometric stress concentrators. The influence of loading regimes on the structural and mechanical properties of a material is reflected at arbitrary loading with the help of the created mathematical models characterizing the hereditary properties of the material and the magnetomechanical effect.