Yarn pull-out behavior under dynamic loading

Jihye Hong, Purdue University

Abstract

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 the 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. To investigate the frictional behavior between yarns in a quantitative and qualitative manner, yarn pull-out experiments have been performed by many researchers. However, available experimental studies were limited to quasi-static, which may not represent the frictional behavior under dynamic loading. Considering that applications for woven fabric materials are under the condition of dynamic loading in many cases, the importance of yarn pull-out experiments at higher rates are evidently great to obtain more realistic results. In this study, we experimentally investigated the mechanical response during the pull out of a single yarn from a single layer of Kevlar ® and Twaron® fabric under out-of plane loading at high rates. In order to perform the dynamic experiments, a system of pendulum impact was designed to pull out the single yarn. The pull-out load was measured directly at the yarn and the movement of the fabric was measured to portrait pull-out load vs. displacement curves. Quasi-static experiments were performed as well to delineate the effects of loading rate. In addition to the rate sensitivity which is the main objective of this study, additional studies on yarn pull-out under in-plane loading at high rates and on the effects of pressure were also performed. Yarn pull-out under in-plane loading was conducted for a direct investigation of the friction between yarns and the effects of pressure were studied since a fabric is used in a multi-layered system in many cases and under impact, and some level of transverse pressure is exerted on each layer by contact with other layers.

Degree

M.S.A.A.

Advisors

Chen, Purdue University.

Subject Area

Aerospace engineering|Textile Research

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