Mesoscale mechanical modelling and experimental measurements of textile composite reinforcements

Woven fibrous textiles as reinforcement of composite materials have received considerable attention in many different industrial applications, due to their improved formability and mechanical properties. Predictive tools are mandatory to avoid time-consuming experimental measurements and to predict and assess the mechanical behaviour of such dry textiles upon variation of several parameters. Their mechanical features have considerable influence during complex shape forming process, in the initial step of the composite manufacturing, and on the mechanical behaviour of final composite components. In this context, the present study deals with the mechanical behaviour of fibrous textiles as reinforcements for composites. A glass plain weave and a hybrid PET/aramid/PET tetraxial textiles were considered. The tetraxial interlacement has warp, weft, and two diagonal yarns oriented at symmetrical angles (typically ±45°) with respect to the warp direction. The aims of the study were: (i) to experimentally observe the deformation and to measure some mechanical properties of the textile reinforcements; (ii) to numerically predict the nonlinear behaviour of the woven fibrous fabrics for any in-plane loading conditions; (iii) to compare the finite element (FE) modelling results to the experimental observations of biaxial tensile and inplane shear loadings. The experimental activities were focused mainly on uniaxial and biaxial extension tests, the latter with different ratio R of the warp to weft displacement rates. Besides, out of plane bending was investigated by cantilever beam test. The numerical study was based on a hyperelastic constitutive model for the yarns material [4]. Assuming the repetitive nature of the considered textiles, the simulation were focused on the Representative Volume (RV), namely meso-scale modelling. The comparison of experimental measurements and numerical predictions highlights the accuracy of the hyperelastic model to predict the nonlinear behaviour of the fabric for any loading condition and to provide the proper numerical model for further optimization investigations of woven fibrous reinforcements