Strain rate effect on the failure behavior of kevlar 49 fabric and single yarn

High strength woven fabrics are ideal materials for use in structural and aerospace systems where large deformations and high-energy absorption are required. Their high strength to weight ratio and ability to resist high-speed impacts enables them to be more efficient than metals in many applications, including ballistic armors, propulsion engine containment systems and fabric-reinforced composites. In order to facilitate the design and improvement of such applications, this study investigates the mechanical behavior of Kevlar 49 fabric and single yarn under quasi-static and dynamic tensile loadings. The experimental results show that the fabric exhibits non-linear in tension, and can deform up to 20% before complete failure under quasi-static loading. The fabric has identical Young's modulus in warp and fill directions, but has different crimp strain, tensile strength and ultimate strain. The sample size has little effect on the mechanical properties of the fabric. The dynamic tensile behaviors of the fabric and single yarn were investigated at strain rates from 25 to 170 s^-1 by using a high rate servo-hydraulic testing machine. Results show that their dynamic material properties in terms of Young's modulus, tensile strength, maximum strain and toughness increase with increasing strain rate.