GDR CNRS 2024
Multiscale Mechanics of fibrous media

At the first stage of the Resin Transfer Molding (RTM) process, the composite reinforcements preforming is a complicated physical stage including complex deformability behaviours. In this paper, the deformability of carbon triaxial braided fabrics, one of the advanced composite reinforcements, is originally investigated. The yarns sliding along both longitudinal and radial yarn directions is the primary preforming behaviour, which is quite distinct from the woven fabrics preforming. Moreover, the yarns sliding along two yarn directions present quite a difference between the axial and bias yarns. The manufacturing defects during the triaxial braided fabrics preforming such as fibre vacancies, buckling and gaps are also discussed. At last, the geometrical models to predict maximum sliding along longitudinal yarn direction are described based on basic preforming parameters. Besides, the criterion preventing fibre vacancies are also proposed.