PSI - Issue 66

2 09

M. Totaro et al. / Procedia Structural Integrity 66 (2024) 205–211

What changes and alters the macroscopic behaviour of the two materials is the fibres response. For BF, the first load loss in the green portion of the curve in Fig. 4a corresponds to the failure of fibre segments in the external regions of the specimen shown in Fig. 5c; while the second load drop, in blue in Fig. 4a, is associated with delamination and debonding shown in Fig. 5d, consisting of separation of plies leading to the material collapse. For GF, in the blue portion of the glass curve in Fig. 4b, a sudden catastrophic failure occurs. Up to this point the specimen appears intact and then experiences a sudden breaking. The failure takes place at the clamping areas (Fig. 5e), either in the lower and upper region. Fig. 6a shows how the lateral fibres breakings appear in Basalt specimens. Then, two types of delamination occur. Two samples are displayed as examples: specimen codified with 3V undergoes a warping of the outer layer; in specimen codified with 2V the first ply separates, followed by the detachment of all plies. (Scalici et al., 2016) also found similar delamination and debonding mechanisms. GF broken specimens are shown in Fig. 6b, with a magnified view of the cross section and side view. In the latter, also a light debonding phenomenon is visible. Also in (Talabari et al., 2019) study, the inter-laminar bonding is high and no layer delamination is observed for vacuum infusion Glass sample. It is possible to affirm that BFRC offer advantages not only from costs and sustainability perspective but also in terms of their failure behaviour, which is highly relevant for design. While showing initial signs of damage, BF components continue to bear the load, allowing the component to survive longer without catastrophic breakage. This suggests that, unlike GF, BF can provide the opportunity to continue using the component after initial damage, enhancing both the safety and durability of the systems in which it is employed.

Fig. 5 Matrix Cracking in (a) BFRC (b) GFRC , (c) BF segments failure, (d) BF delamination, (e) GF breaking