PSI - Issue 37

Evangelia Nektaria Palkanoglou et al. / Procedia Structural Integrity 37 (2022) 209–216 E. N. Palkanoglou et al. / Structural Integrity Procedia 00 (2019) 000 – 000

215 7

10 15 20 25 30 35 40

min distance max distance

360 380 400 420 440 460 480 500 0 5

Fraction of debonded areas (%)

Temperature (  C)

Fig. 4: Effect of vermicular inclusion on onset and propagation of thermal decohesion of nodular inclusion.

In contrast, the decohesion of a vermicular inclusion when interacting with a nodular one was much smaller (Fig. 5). In this case, debonding appeared at the highest temperature (compared to all the other cases examined here), and the fraction of debonded areas was the lowest. A nodular inclusion prevented the concentration of stresses due to interaction on the sharp edges of the vermicular inclusion, decelerating its fracture as well as limiting the areas that lost their contact with the matrix. In essence, the nodular inclusion seemed to have a shielding effect on the neighbouring vermicular particle in terms of decohesion.

2

1

min distance max distance

420 430 440 450 460 470 480 490 500 0 Fraction of debonded areas (%)

Temperature (  C)

Fig. 5: Effect of nodular inclusion on onset and propagation of thermal decohesion of vermicular inclusion.

4. Conclusions Interaction between the neighbouring particles in CGI and the influence of this phenomenon on graphite fracture is investigated in this paper. A two-dimensional unit cell comprising two inclusions was developed, based on statistical analysis obtained by microstructural characterisation. An elastoplastic constitutive behaviour was assumed for both