Evaluation of microstructural parameters for micro/macro-line crack damage model

Considered is a line crack model that can account for multiple unsymmetrical microcracking patterns even the applied macrostress is symmetrical across the plane of the initial microcrack. The multiple unsymmetric micro-branchings arise from the three essential parameters that are implicit in the micro/macro-model. They account for the inhomogeneity and/or anisotropy of the material. Matching of the analytical predictions from the assumed fracture criteria and the physical observations are problem specific and subjective. The work prepares the ground for the development of the general scheme known as the physical–analytical matching approach. The main objective is to link the results found from several size and time scales that are referred to as multiscaling. Demonstrated is the linking of macro- and micro-effects. In particular, the model will show that micro-unsymmetry need not be explicitly invoked in the macro-geometry and/or loading. The double singularity line crack model shows that a variety of single, double and triple branching patterns can be predicted from the volume energy density criterion in contrast to the maximum stress criterion that is limited in predictive capability.There is no loss in generality by using a linear analysis as long as the scale range is segmented to exclude non-linearity. Moreover, the emphasis on the energy level and characteristic length of the micro- and macro-defects rather than precise geometric shape of the defect which can be a line, notch or other configurations. Such an approach is justified by the existence of a hierarchy of spatial and temporal combination of the material damage process. The ones that are commonly encountered are the macromechanical, microstructural and nanochemical. This study is concerned with the microstructural where macro-loading applied to a structural body can introduce microcracking because of the interaction of inherent microscopic defect with the material internal structure.