1. Principal tensile stress near the 11/12 joint ↓

2. Development of the cracks near the 11/12 joint ↓

3. Development of the cracks near the 11/12 joint ↓

4. Development of the cracks near the 11/12 joint ↓

5. Distribution of principal tensile stress near the 11/12 joint ↓

6. Distribution of principal tensile stress near the 11/12 joint ↓

7. Displacement of failure process near the 11/12 joint ↓

8. Failure process (with initial cracks) ↓