Analysis of the hygroscopic and hygroelastic behaviours of water aged flax-epoxy composite

Belahcen Djellouli (1) , Wajdi Zouari (1) , Mustapha Assarar (1) , Rezak Ayad (1)

1 ITheMM - Institut de Thermique, Mécanique, Matériaux

In this paper, an analysis of the hygroscopic and hygroelastic behaviours of unidirectional flax fibre-reinforced epoxy composite is presented. Samples of this composite material were elaborated by the vacuum infusion process, then cut and prepared to be aged in tap water until saturation. To describe their hygroscopic behaviour, Fick’s model is considered and an optimisation procedure is developed to identify their macroscopic water diffusion parameters. After that, a plane finite element modelling of the hygroscopic behaviour of the aged flax-epoxy samples is conducted to identify the flax fibre radial and longitudinal water diffusion parameters using an inverse approach. Finally, a plane finite element analysis of their hygroelastic behaviour is proposed allowing the estimation of the hygroscopic internal stress in flax fibres and epoxy matrix. In particular, the hygroscopic analysis reveals that water diffusion is more pronounced in the direction of flax fibres compared to the transverse and thickness directions. In addition, the hygroelastic finite element modelling highlights the high compressive and tensile stress subjected to flax fibres and epoxy matrix, respectively, due to water absorption.

Mots clés: Composite lin-époxy; Analyse hygroscopique

Domaines: Sciences de l'ingénieur [physics]

Belahcen Djellouli, Wajdi Zouari, Mustapha Assarar, Rezak Ayad. Analysis of the hygroscopic and hygroelastic behaviours of water aged flax-epoxy composite. Composite Structures, 2021, 265, pp.113692. ⟨10.1016/j.compstruct.2021.113692⟩. ⟨hal-03339446⟩