Three-dimensional (3D) woven textile-reinforced composites have drawn much attention because of their specific geometries, improved composite interlayer strength, and impact-resistance performance. In this study, three types of 3D woven structures with different binder-yarn ratios and paths were designed based on a traditional dobby-weaving loom with a special weft-interlock structural design. Carbon/aramid fiber-reinforced plastic (CAFRP) composites with carbon warp, weft, and aramid binder yarns, as well as carbon fiber-reinforced plastic (CFRP) composites were reinforced using the three types of woven structures and consolidated with epoxy resin. The quasi-static and dynamic flexural performance of these 3D woven composites were experimentally investigated using a three-point bending test and a low-velocity drop-weight impact test. Nondestructive ultrasonic C-scan and X-ray microcomputed tomography were applied to characterize the failure mode of the impacted composites. Woven structure and aramid binder yarn with a coarse count have a coupling effect on the quasi-static flexural performance of the 3D woven CAFRP composites. A larger volume combined with a smaller throughthickness waviness degree of aramid binder yarn has a similar effect with a smaller volume combined with a larger waviness degree. Introducing aramid binder yarn in the hybrid composites lowered the quasi-static flexural performance to a certain extent (0.28%-47.74% and 5.29%-49.63% for flexural modulus and strength, respectively) but increased the impact performance significantly (e.g., increasing 23.6%-92.7% peak-load values under 6-J impacts).A larger volume combined with a smaller waviness degree of the aramid binder yarn introduced in these woven structures contributed more to impactresistance and damage-tolerance performance.

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In the present research, a physical-geometric-feature of continuous yarn in a plain woven fabric was created and its FE model was analysed by considering the two key issues of woven fabric, the crimp and inter-yarn friction. The basic parameters of Young’s modulus of single yarn and the inter-yarn friction coefficient were investigated for practical fabrics in tensile and pull-out tests. FE analysis indicated that the stress-strain curves of the FE model were effective in evaluating the equivalent modulus of a woven fabric by comparing with a tensile experiment on Twaron CT® Plain Woven Fabric. In addition, a simplified three dimensional model of the unit cell of plain woven fabric (UCPW) was employed to quantitively investigate two important fabric characteristics – the crimp rate of the yarn and inter-yarn friction-to determine their influence on the mechanical properties of the fabrics. Furthermore, we used FE analysis to evaluate how the crimp rate and inter-yarn friction affected the mechanical properties by determining the equivalent modulus of single yarn and UCPW in both uniaxial and biaxial tensile loading. The stresses at representative nodal points and the mechanical interaction between yarns were also investigated from a microscopic perspective, and their deformation mechanisms were also analysed and discussed.