Effect of electrospun PA66 nanofibrous mat thickness on mode-II fracture toughness using acoustic emission (AE) with data clustering technique

• Published in: Theoretical and applied fracture mechanics 2023-04, Vol.124, p.103788, Article 103788
• Main Authors: Salimi-Mofrad, H., Rahbar Ranji, A., Saghafi, H.
• Format: Article
• Language: English
• Subjects: Acoustic emission; Electrospinning; Mode-II fracture toughness; Nanofibers
• ISSN: 0167-8442; 1872-7638
• DOI: 10.1016/j.tafmec.2023.103788

•Investigating the PA 66 nanofibrous mat thickness effects on the Mode-II fracture toughness in laminated composites.•Effective parameters in lowering the Mode-II fracture toughness by increasing the PA66 nanofibrous mat thickness.•Delaying crack initiation and controlling crack propagation rate by interleaving PA66 nanofibrous mat between GFRP UD plies. Considering the importance of improving the fracture toughness of composite laminates, in this research, by embedding electrospun nanofibers of polyamide 66 between the layers, the fracture toughness of prepared samples was evaluated in Mode-II loading and compared to the reference state. It was demonstrated that adding polyamide 66 nanofibers of two distinct thicknesses, 110 and 140 μm increased the fracture toughness in mode-II by 84 % and 47 %, respectively. Thus, there is an optimum value for thickness of nanofibers to have maximum enhancement of fracture toughness. Additionally, the acoustic emission method was used to examine the key features that increased fracture toughness. Using acoustic emission features and hierarchical model clustering, it was shown that fiber/matrix debonding is the primary damage mechanism lowering the mode-II fracture toughness. Macro pictures and SEM micrographs were used to observe the failure mechanisms on the sample surfaces.