Effect of Loop Yarns on Mechanical Properties of Carbon Fibre/Epoxy Composites

The general two-dimensional (2D) woven laminated composite (GWLC) is widely used in aviation, aerospace and high speed railways, and its superior specific stiffness and strength substantially reduce the weight of the structural components. However, when the GWLC is damaged by flexural, shear and impact loads, the layers are prone to delamination. To improve the interlayer properties of the GWLC, a loop warp yarn is added to the plain fabric by means of three-dimensional (3D) weaving technology, resulting in a double-side-loop fabric with Z-directional fibers. This paper investigates the double-notched shear (DNS) properties, in-plane shear properties, and flexural properties of GWLC and a new double-side-loop 2D woven laminated composite (DWLC). The test results verify that adding the loop warp yarns can greatly improve the interlayer properties of the general 2D woven laminated composites. The DWLC increases the interlaminar shear strength by 81.5%, the in-plane shear strength by 49.4%, and the flexural strength and modulus by 90.2% and 61.4%, respectively. The excellent mechanical properties of the DWLC lay a foundation for loop fabrics in engineering applications.