FE simulation and experimental study of tensile behavior and progressive failure of 3D stitched twill fabric reinforced aluminum matrix composites

This paper aimed at exploring the complex damage and failure mechanisms of a novel aluminum composites reinforced with 3D stitched twill fabric. The uniaxial tensile behaviors, especially progressive failure of the composites, were investigated by multiscale modeling and experimental method. Mechanical properties of the fiber bundle, which was impregnated with aluminum alloy, were predicted by a micromechanical model at fiber scale. According to the 3D fabric architecture, a mesoscopic finite element model at fiber bundle scale was established to analyze the damage evolution and failure behaviors of the composites. The homogenized stress-strain curve from the multiscale simulation is basically coincident with the experimental ones, where the elastic moduli, tensile strength and elongation is 129.6 GPa, 630.2 MPa, and 0.76%, respectively. The periodic distributions of local stress in the composites are closely related to the special fabric architecture. Local damage germination of matrix pocket and transverse cracking of weft and stitch bundles initiate and develop gradually at the early and middle tensile stage. The axial fracture of warp bundle and matrix failure that occurs at the final stage lead to the catastrophic rupture. The failure modes from numerical simulation were further verified and discussed by comparing with the fracture morphology of the composites. In addition, the mechanical response and failure behavior under weft directional tension were preliminarily analyzed by using the validated multiscale model.