Influent Fabric Parameters on the Energy Absorption During Dynamic Tensile Loadings
Résumé
Based on numerous research works [1] [2] [3] [4] [5] [6], fabric parameters such as: the yarn’s properties, the yarn-to-yarn friction coefficient and the distribution of end and pick densities, have been revealed as influent on the energy absorption mechanism during ballistic impact. However, most of these parameters are measured at quasi-static velocity while the ballistic impact involves high strain rate. Knowing the dynamic behavior of a yarn inside the woven structure is essential to determine the ballistic behavior of fabrics during an impact. This work aims at studying the mechanical behavior of a para-aramid yarn inserted in a fabric structure during a dynamic and longitudinal load. To that end, we have designed a new experimental device to achieve these tests with the use of a gas gun: the Tensile Impact Test for Yarn (TITY). Many test campaigns have been performed to identify the influence of weave diagram, and consequently the number of crossover points between warp and weft yarns for the same pick density and for each fabric, and the energy absorption during dynamic loading of the yarn inserted in the woven structure up to its rupture. This study reveals the influence of three main structural parameters such as: the total inter-yarns contact surface, the number of binding points and the transverse and lateral inter-yarns pressures. These influent parameters have an impact on different yarn break criteria at different scales of the fibrous material, such as: the structural defects and hysteresis phenomena inside the filament, stress concentrations and frictional forces concerning the interactions between the tested yarn and the rest of the fabric.