The dynamic fracture behavior of brittle materials that contain micro-level cracks should be examined when material subjected to impact loading. We investigated the effect of micro-cracks on the propagation of macro-cracks that initiate from notch tips in the Kalthoff-Winkler experiment, a classical impact problem. To define pre-defined micro-cracks in three-dimensional space, we proposed a two-dimensional micro-crack plane definition in the bond-based Peridynamics (PD) that is a non-local form of classical continuum theory. Randomly distributed micro-cracks with different number densities in a constant area and number in expending area models were examined to monitor the toughening of the material. The velocities of macrocrack propagation and the time required for completing of fractures were considered in several pre-defined micro-cracks cases. It has been observed that toughening mechanism only initiated by exceeding a certain number of micro-cracks; therefore, there is a positive correlation between the density of pre-defined microcracks and macro-crack propagation rate and also, toughening mechanism.
|Journal||Journal of Engineering Materials and Technology|
|Publication status||Accepted/In press - 17 Jun 2020|
- crack initiation