The Tensile Properties of Three Dimensional Air Textured Aramid Reinforced Composites

Air-textured aramid yarns (ATAY) and regular aramid yarns (RAY) were used in this study to fabricate 3D orthogonal woven composites. The composites were tested in warp, weft, and 45° directions to determine the engineering constants of the composites. The ATAY composite had a much lower fiber volume fraction than the RAY composite due to the bulkiness of the textured yarns. With the same fiber volume fraction, the ATAY composite had a slightly lower tensile strength and modulus, but a 120% higher in-plane shear modulus, than the RAY composite. Unlike the RAY composite that demonstrated a brittle failure, the ATAY composite failed in a ductile manner with multiple diverting cracks propagating during failure. The ATAY composite had a much higher yield point in the 45° direction tensile test and a much higher softening point in the warp direction tensile test than the RAY composite. The loop entanglements of ATAY are responsible for all the improvements observed in this study.