Issue 68

M. C. Chaves et alii, Frattura ed Integrità Strutturale, 68 (2024) 94-108; DOI: 10.3221/IGF-ESIS.68.06

accompanied by surface defects like bubbles, a byproduct of the manufacturing process. Additionally, the matrix shows areas of fiber-matrix adhesion and fiber-matrix debonding, an occurrence assumed to be a consequence of stress transfer between them.

Figure 13: Strain-life curve for the BioPoxy-fique composite.

Figure 14: Cross-section of a sample tested at a 130% strain level.

Since complete fracture was not achieved during fatigue tests, some samples were ruptured using liquid nitrogen. Fig. 15 reveals fiber pullout, a phenomenon dependent upon the strength of the fiber-matrix union and the associated stress transfer mechanisms. The fiber ends exhibit characteristics of a brittle failure mode. Additionally, the presence of river marks is noteworthy, indicating damage to the matrix. These marks signify a loss of cohesion in the material, serving as evidence of structural degradation.

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