Influence Of The Air-Textured Aramid Yarn On The Mechanical Behavior Of The Three-Dimensional Woven Thermoset Composites

The goal for texturing yarn in traditional textile applications is to increase bulk, enhance hand, and increase extensibility of a yarn. Develops for texturing high modulus and strength yarns have shown a great potential for new opportunities for using these yarns in composites applications.Karger and Czigany reported that commingled textured glass and polypropylene yarns were shown to raise the energy necessary to propagate a crack through a composite structure and to alter the characteristic of impact energy distribution through the structure. Lauke et al also reported that using air-textured glass yarn can improve the crack resistant properties of thermoplastic composite materials by creating fibers that interfere with crack propagation. Air-textured yarns provide more surface area due to the loop structure that has the potential to improve interlaminar shear strength in a laminate composite by higher adhesive strength and by "hooking" across from yarn to yarn. Briscoe et al found that the weave and surface texture had pound effect on the interlaminar fracture toughness of aramid/epoxy laminates.The purpose of this study was to investigate the performance of air-textured aramid yarn (ATAT) in a 3D woven fabric reinforced composite. Yarn tensile test demonstrated that air-textured yarn was 70% lower in the tensile strength, 83-85% lower in tensile modulus, and 100% higher in failure strain than those of the regular aramid yarn (RAY). The ATAY composite had a much lower fiber volume fraction than the RAY composite due to the bulkiness of the textured yarns. With the samefiber volume fraction, the ATAY composite had a slightly lower tensile strength and modulus than the RAY composite. Unlike the RAY composite, the ATAY composite failed in a more brittle manner along the air-textured yarn. ATAY can increase the interlaminar shear strength of a laminate composite by 27% as compared with the control. This is because the fluey structure of the ATAY increases the adhesive strength between the ATAY and the matrix. In the low-velocity drop weight impact test, although the peak load undertaken by the ATAY composites is much higher because of its higher thickness, the damage threshold energy and total energy absorbed by the RAY composite are higher than that of ATAY composite. This is also due to the better adhesive strength between the ATAY and the matrix, which preventing the crack propagation in more directions and reduced the delamination areas.