Mechanical behaviour of dry fabric reinforcements. 3D simulations versus biaxial tests

The knowledge of the mechanical behaviour of dry woven fabrics is necessary in many applications. The aim of this study is to recall the specificity of the mechanical behaviour of dry fabrics and to understand the local phenomena that influence the macroscopic behaviour. For this, 3D finite element analyses of elementary patterns are performed. These calculations are not classical due to the constitution of the yarns made of a lot of small fibres. The possible motions of the yarns allow changes of undulation leading to nonlinear biaxial tensile behaviour and the lack of most of the other stiffnesses. The specificities of the calculation in order to reach this behaviour are described. The model is compared to biaxial tests on several fabrics. Such a model allows to understand the phenomena implicated in the behaviour and the main aspects that lead to the specific behaviour of woven media. It can also bring a help for the design of new fabrics in changing some mechanical and geometrical parameters in order to get prescribed properties.