Perpendicular Yarn Pull-out Behavior under Dynamic Loading

Multi-layers of woven fabric, characterized by high strength, high flexibility and low density, have been widely used for protective systems, from bulletproof vests to turbine engine fragment barriers. Under ballistic impact, the kinetic energy of the projectile is absorbed by the fabrics deforming largely in out-of- plane direction, which retards the motion of the projectile. Interfacial friction between yarns is known as one of the factors that affect the energy absorption by the fabric. In this study, we experimentally investigated the mechanical response during the pulling out of a single yarn from a single layer of Kevlar® or Twaron® fabric at high rates. In order to perform the dynamic experiments, a pendulum impact was generated to pull out the yarn. Displacement was measured from a noncontact laser system and pull-out force signal was received by a quartz transducer connected to the yarn being pulled out. Quasi-static experiment was also performed to study the effects of loading rates on the mechanical response when a yarn is pulled out perpendicular to the fabric plane.