Bending properties of reinforcements in composites

This chapter discusses with the out-of-plane bending deformations in the shaping of composite reinforcements, because taking them into account would give more accurate simulations of forming, especially for stiff and thick textiles. It starts by presenting the bending modeling at macroscopic scale and the classical bending tests, namely Peirce cantilever test and Kawabata bending test, with their limits. It then introduces different bending tests developed in last decades and based on the cantilever test or three-point bending test and using optical measurement. These developments allow to derive the relation between the bending moment and the curvature. In particular, it is shown how improved cantilever tests allow for the determination of nonlinear bending behaviors. In addition to the overview of these new experimental tests, this chapter focuses on a new flexometer designed for testing composite reinforcements and using optical measurements. Direct method identification and inverse identification were applied to characterize carbon fabrics, and the results are discussed.