Exploration of Wave Development during Yarn Transverse Impact

Abstract

Abstract:Single yarns have been impacted in a transverse fashion so as to probe the characteristics of resulting wave development. Longitudinal wave speeds were tracked in efforts to directly measure the yarn tensile stiffness, resulting in a slight increase in the modulus of Kevlar R KM2 and Dyneema R SK76. Additionally, the load developed in AuTx R and Kevlar R KM2 yarns behind the longitudinal wave front has been recorded, providing additional verification for the Smith relations. Further effort to bolster the Smith equations has been successfully performed via tracking transverse wave speeds in AuTx R yarns over a range of impacting velocities. Additional emphasis has been placed at understanding the transverse wave development around the yarn critical velocity, demonstrating that there is a velocity zone where partial yarn failure is detected. Above the critical velocity, measurement of early time transverse wave speeds also agrees with the Smith solution, though the wave speed quickly reduces in value due to the drop in tensile stresses resulting from filament rupture. Finally, the Smith equations have been simplified and are compared to the Cunniff equation, which bear a striking resemblance. Due to such a resemblance, it is suggested that yarn critical velocity experiments can be performed on trial yarn material, and the effect of modifying yarn mechanical properties is discussed.

A filament-level analysis on failure mechanism and ballistic limit of real-size multi-layer 2D woven fabrics under FSP impact

“…[4][5][6][7] However, its inconsistency under high-speed impact circumstances has drawn attention in recent years with regard to yarn and single-fiber transverse properties. Hudspeth et al 8 systematically investigated the wave development of multi-fiber tow during transverse impact by sharpedge razor blade, fragment simulating projectile (FSP), and round nose projectile. The experimental results show the longitudinal wave speed of the razor blade is generally lower than that of FSP and round nose projectile.…”