3D Microcracking networks of stitched multiaxial laminates under thermal loadings
Résumé
Until recently, structural composites used in the aeronautical industry were still manufactured by the traditional process based on prepregs autoclaving. But occurrence of stitched multiaxial laminates NCF (Non Crimp Fabric) conducts to a new type of high performance preforms for manufacturing complex composite structures by RTM (Resin Transfer Moulding) or infusion process. However, they have a particular morphology as well as a spatial heterogeneity with resin-rich regions inside the material. In this study, a specific 3D cracking network was found out within the resin regions after the material has been subjected to thermal fatigue. The aim of this work is to focus the resin-rich regions due to stitching yarn section, which are the cause of the specific crack network under thermal cyclical loading, and not the resin-fibre heterogeneity at general composite micro-scale. In order to characterise the microcracking and determine the effect of resin-rich regions on crack initiation and propagation, a cyclical thermal loading is defined and is applied. A refined analysis relying on X-ray microtomography is carried out on test specimens, periodically.
Origine : Fichiers produits par l'(les) auteur(s)
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