PSI - Issue 33

Daniele Gaetano et al. / Procedia Structural Integrity 33 (2021) 1042–1054 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Table 2. Mixed-mode fracture properties of the cohesive interfaces embedded in the pre-preg layer. Interface K n = K s (N/mm 3 ) σ nn (MPa) σ sn (MPa) G I c (N/m) G II c (N/m) Fiber/matrix 1.56×10 9 25 25 50 50 Matrix/matrix 1.56×10 9 50 50 50 50

The related numerical results, in terms of both the complete overall stress-strain response and the global damage evolution law, are reported in Fig. 6.

Fig. 6. Uniaxial tensile homogenized traction-separation law (A) and isotropic damage evolution function (B) for the pre-preg layer.

In particular, as explained in Section 3, the complete macroscopic stress-strain response reported in Fig. 6 has been projected at the crack level to derive the homogenized cohesive traction-separation law, to be used at the macroscopic level. Such a law, reported in Fig. 7B for the given microstructure, is simply obtained by considering only the softening branch of the entire overall interface response illustrated in Fig. 7B.

Fig. 7. Derivation of the homogenized traction-separation law per the pre-preg layer.