13th International Conference on Fracture June 16–21, 2013, Beijing, China -4- 0 2 4 6 8 1012141618202224 0.00 0.05 0.10 0.15 0.20 2as=15mm R=0.1 σmax=60MPa am: about 22mm Fit Curves COD/mm x/mm am: about 17mm Figure 5. Variation of crack opening contour As shown in Fig. 5, the crack opening contour can be described as: be maximum value near the tip of saw-cut, decline rapidly along the crack propagation direction, remain almost a constant value in the middle, and decrease to zero at the tip of the crack. Based on the distribution of data, it can be fitted to time by cubic polynomial equation perfectly. 0 2 4 6 8 101214161820 0.00 0.05 0.10 0.15 0.20 0 4 8 12 16 20 2as=10mm am: about 17mm R=0.1 σmax=85MPa COD/mm x/mm σmax=60MPa Figure 6. Influence of stress level on crack opening contour 0.00 0.05 0.10 0.15 0.20 -5 0 5 10 15 20 -5 0 5 10 15 20 25 σmax=60MPa R=0.1 x2as=15mm/mm 2as=15mm COD/mm 2as=10mm x2as=10mm/mm Figure 7. Influence of saw-cut length on crack opening contour (c) 2as=15mm 2as=10mm
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