Analysis of the in-plane shear behavior of biaxial non-crimp-fabric at mesoscopic scale

Understanding the mechanical properties of carbon fibre reinforcements is necessary for the simulation of forming processes, where the in-plane shear is one of the basic deformation mechanisms. In this paper, the shear deformation mechanics of warp-knitted 0°/90° carbon fibre biaxial non-crimp fabric (NCF) were experimentally investigated based on a bias-extension test. For NCF, the interplay sliding and the development of gap between fibre yarns caused by stretched stitches are two mechanisms which differ from those observed in woven fabrics and are challenging to directly detect through macroscopic studies that treat the entire structure as a continuous medium. A mesoscopicscale representative unit cell model with accurate geometrical parameters was utilized to conduct an inplane shear simulation. The local deformation of fibre yarns and stitches including the change of width and the development of gap can be visualized and the normalized shear force were compared between the experimental results and simulation results.