Issue 56

H. Bai et alii, Frattura ed Integrità Strutturale, 56 (2021) 16-45; DOI: 10.3221/IGF-ESIS.56.02

Figure 15: Crack layout.

Characteristics of the crack propagation process Comparative analysis of crack initiation modes Tab. 5 is a comparison table of the crack initiation modes of the ductile group. The content of epoxide resin and polyamide is gradually reduced from left to right, that is, the brittleness of the material is gradually increased. By comparing and analyzing Tab. 5, it can be seen that as the content of epoxide resin and polyamide decreases gradually, the new crack initiation mode gradually changes from the state where the initial wing crack and shear crack coexist to only the wing crack. Through the observation of the experimental loading process and the analysis of the experimental data, it is found that there is no significant difference in the vertical compression displacement of each specimen when the new crack starts to sprout.

G5

G4

G3

G2

G1

G3

G5

G2

G4

G1

20mm

20mm

20mm

20mm

20mm

G2

G4

G1

G3

G5

a- wing crack b- shear crack c- wing crack d- shear crack

a- shear crack b- wing crack c- wing crack d- shear crack

a- shear crack b- shear crack c- wing crack d- wing crack

a- wing crack b- wing crack c- wing crack d- wing crack

a- wing crack b- wing crack c- wing crack d- wing crack

Table 5: Crack initiation mode of the ductile group.

36