13th International Conference on Fracture June 16–21, 2013, Beijing, China -7- In order to investigate the effect of crack location, several RVEs with three different crack locations were cut from the actual size model: a center crack, a 20mm off-center crack and a 40mm off-center crack are plotted in Fig. 9. By increasing the loading step, the damage around the crack tip will grow until eventually the first element will reach to the critical damage parameter, cD . At this stage the new crack tip coordinates will be determine by a self-compiled searching program and the crack will advance as much as the new crack tip point. This progress continues until final failure of the specimen. The experimental [12] and numerical crack paths of three crack locations are plotted in Fig.3 and Fig. 4, the simulation results showed good agreement with the experimental paths. Due to the similar coarse aggregate distribution, the simulation results were similar to the results computed by the fracture criterion based on the maximum circumferential tensile stress especially. The damage-based fracture criterion is validated to feasible by the comparison. Furthermore, the paths of this paper predicted showed agreement with the experimental paths more closely than the curves given by Yin et al. [12] in some regions. Then it can be proved the effect of aggregate is more significant to the damage evolution. Form total comparison it can be seen the father the crack is away from the beam center, the larger its kinking angle is. But the crack trends to grow towards to the beam top midspan. (a) Actual size FEM model for crack location 0mm (b) Actual size FEM model for crack location 20mm (c) Actual size FEM model for crack location 40mm
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