Effect of triaxial woven fabric on bending properties of unidirectional composites

This study investigates the impact of incorporating a triaxial woven fabric (TWF) into a unidirectional ply structure on the bending performance of the structure. The failure processes of the different ply structures were recorded using video analysis and acoustic emission. The experimental results indicated that incorporating a layer of carbon fiber TWF between the second and third layers (GGTGG) or between the third and fourth layers (GGGTG) of the four-layer unidirectional fabric significantly improved the flexural strengths by 79.5% and 213.7%, respectively, and the flexural toughness by 480.3% and 324.8%, respectively. In addition, the incorporation of TWF in the structure resulted in a shift in the overall failure mode from brittle to ductile. When the TWF was closer to the lower surface of the sample, the crack was more uniform and the distribution range was wider. In contrast when the TWF was in the middle, the range of cracks generated by the sample was narrower. However, some of these cracks affected the stability of the material structure. Furthermore, the damage process was confirmed using images of crack growth and acoustic emission during the destruction process. This study provides valuable insights into enhancing the bending performance of unidirectional fiber layup in the non-load direction.