MODELING OF DEFORMATION AND FRACTURE PROCESSES ON THE MESOLEVEL

A new unified approach to the modeling of the deformation and fracture processes in materials with complex internal structure on different scale levels is presented. It is shown that the macroscopic phenomenological methods are inadequate for the description of these processes, especially in the cases where the local values of the parameters and inhomogeneity of the internal structure are considerable. In the context of physical mesomechanics, we consider the methodology of this problem and specific features of the construction of the constitutive equations for plastic deformation, which take into account the contribution of the microand mesolevel flows to the resistance. The behavior of a representative mesovolume is modeled by explicitly taking into account the structural inhomogeneity of this mesovolume. A simple model is suggested to take into account possible rotations of mesofragments (grains, solid inclusions, etc.) caused by the evolution of the internal micro- and mesostructure of the material subjected to a loading. The mesoscale level plays a leading part in the analysis of the strain localization and modeling of the sigma- epsilon relation for the case of large plastic strains. Illustrative numerical results are presented and analyzed.