Hygrothermal effects on fatigue behavior of quasi-isotropic flax/epoxy composites using principal component analysis
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This work studies the long-term hygrothermal (HT) aging effect on the fatigue behavior of a flax/epoxy bio-composite arranged in [02/902/±45]S lay-ups. The effect of aging on static tensile mechanical properties was first investigated. Tension–tension fatigue tests were also performed for both unaged and aged samples. The distribution of fatigue life for both unaged and aged sample was determined. The evolution of fatigue properties was also investigated. Fatigue tests were coupled with acoustic emission (AE) for a better understanding of how these composites react to fatigue loading in wet environmental conditions. Static tests show that water absorption affects negatively the elastic properties of this material. S–N curves show a good performance in fatigue strength of unaged samples. This performance dropped significantly with HT aging. The analysis of stress–strain hysteresis loops allowed to determine the minimal strain such as the desirable fatigue properties to explain fatigue damage evolution for single stress component. Hwang–Han’s model based on minimal strain was also used to predict the fatigue damage of the tested flax/epoxy composites. Principal component analysis enabled to separate the fatigue damage evolution of unaged and aged samples. AE results confirmed that the damage evolution of both samples is not the same. AE analyses were permitted to identify the growing fiber/matrix debonding and pull-out mechanism in the unaged samples. Correlation between AE and scanning electron microscope observations enabled the identification of several damage mechanisms and their evolution during the fatigue tests.
KeywordsFatigue Acoustic Emission Fatigue Life Fatigue Behavior Damage Evolution
The authors would like to acknowledge the financial support of the natural sciences and engineering research council (NSERC) of Canada through its discovery Grant Numbers 138039–2012 and 386284–2010.
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Conflicts of interest
The authors declare that they have no conflict of interest.
- 5.Sodoke KF et al (2016) Fuzzy logic response to Young’s modulus characterization of a flax–epoxy natural fiber composite. Mater Des 89:273–285Google Scholar
- 22.Kersani M, Lomov SV, Ver Vuure AW, Bouabdallah A, Verpoest I (2014) Damage analysis based on the correlation between acoustic emission and E modulus degradation in flax/epoxy quasi unidirectional woven laminates. In:16th European conference on composite materials, ECCM 2014 Google Scholar
- 23.Saidane EH, Scida D, Assarar M, Ayad R (2014) Effects of manufacturing process and water ageing on the mechanical behaviour of two reinforced composites: Flax-fibres and glass-fibres. In 16th European conference on composite materials, ECCM 2014Google Scholar
- 32.A. Fotouh and J. Wolodko (2011) Fatigue behavior of natural fiber reinforced thermoplastic composites in dry and wet environments. In ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE, 2011, pp. 71–77.Google Scholar