Effect of aging on the fatigue crack growth properties of carbon-polyamide 6 thermoplastic composites using the multi ΔG-control method

• Published in: Composites. Part A, Applied science and manufacturing Applied science and manufacturing, 2022-10, Vol.161, p.107105, Article 107105
• Main Authors: Arhant, Mael, Lolive, Eric, Bonnemains, Thomas, Davies, Peter
• Format: Article
• Language: English
• Subjects: Fatigue crack growth; Hydrolysis; Molar mass; Sciences of the Universe; Thermoplastic composites
• ISSN: 1359-835X; 1878-5840
• DOI: 10.1016/j.compositesa.2022.107105

•The multi-ΔG control method was successfully used to investigate the effect of hydrolytic aging on fatigue crack growth properties.•The Hartman-Schijve relationship accurately describes the changes in mechanical behaviour induced by wet aging.•Fatigue crack growth properties are highly dependent on the molar mass Mn.•Fatigue crack growth properties are more sensitive to aging than quasi-static fracture toughness. This paper focuses on the fatigue crack growth behavior of unidirectional C/PA6 composites subjected to hydrolytic aging at temperatures ranging from 100 to 140 °C. The fatigue crack growth properties were determined using a multi-ΔG control test method. The latter is fully automatic and allows measurement of crack growth rates at various ΔG levels. It was shown that the fatigue crack growth properties were highly affected by aging. Whatever the aging temperature, the crack growth rate was increased by about a decade after aging, and the fatigue crack growth properties are highly dependent on the molar mass. Finally, it was shown that the traditional Paris law does not allow a full description of the behaviour so the Hartman-Schijve relationship was applied to characterize the fatigue response.