sample had the largest radiation area, and the shape tended to be a regular circle. Secondary microcracks with high density were evenly distributed in the radiation area. This indicated that the sample's structure was relatively uniform. The radiation area of sample 2# was an irregular oval with a small area. In contrast, the shear lip area was large.

comparing the macro morphology of these four samples, it can be seen that all the fracture morphologies were typical cup-shaped vertebrae, which was their common point.

secondary cracks, which generally presented the characteristics of brittle fracture. The

the radiation area was a regular circle with a large area. The regularity of the fracture morphology of sample 7# was the worst, where the fiber area was far away from the center of the circle, the morphology of the radiation area was irregular, and the radiation area was very uneven with a large number and distribution of long and deep cracks. In

, 6# and 7# are shown in Figure 9. By
