Longitudinal failure mechanisms and crack resistance curves of unidirectional thermoplastic composites

• DOI: 10.1016/j.engfracmech.2023.109147
• Publication Date: 2023-02-25T03:13:10Z
• Authors: Federico Danzi; Pedro J. Silva Ca...; Albertino Arteiro; Denis Dalli; Carolina Furtado; Jérémy Chevalier; Rodrigo P. Tavares; Frédéric Lani; Pedro P. Camanho
• Keywords: 02 engineering and technology; 0210 nano-technology

This paper presents a study on the longitudinal fracture toughness, and associated crack resistance curves, of thermoplastic-based composite materials. Double-edge notched (DEN) specimens loaded in tension and compression are used to relate the size-effect laws with the crack resistance curves of unidirectional carbon-fibre reinforced PEKK. The results are corroborated with SEM and fractographic images to provide a better overview of the main failure mechanisms involved during the failure process. Moreover, tensile tests interrupted at 90% of the estimated failure load are CT-scanned to highlight the early stages of the crack propagation. This investigation confirms the suitability of the size-effect method for characterizing thermoplastic composites and it stands out as a first qualitative and quantitative analysis of their characteristic intra-laminar failure mechanisms. © 2023 The Author(s)