Effect of replacement strike-face material on the ballistic performance of multi-ply soft armor targets

Self Cite

Upon impact with a target panel, a portion of a projectile's striking kinetic energy is dissipated via heat loss or deformation. Typical ballistic performance determination standards require strict projectile hardness values of Rc 29 ± 2 for consistency and repeatability, but it is of interest to examine if these required hardness values give a lower bound where the ballistic performance determination is independent of the strength of the projectile. In this study, a large range of yield strengths of metallic right-circular cylinders were used to test the effects on the ballistic response of a multi-ply soft body armor. The results show that with an increase in projectile yield strength, the ballistic limit velocity decreases. This degradation in ballistic performance of the soft armor target levels off at higher yield strengths to about 75% of the expected ballistic performance for Rc 29, indicating that there may be a minimum projectile strength after which the influence of strength is no longer significant. The degree of deformation of projectiles during impact is related to the striking velocity and the off-axis failure of the soft armor target material.

Section: Impact Flash Phenomenasupporting

confidence: 86%

Projectile strength effects on the ballistic impact response of soft armor targets

Guo

Martinez-Morales²,

Chen

2019

Self Cite

“…10–12 Similar phenomena were also observed on dry fabric panels by Guo et al. 13 The fact that different layers of fabric exhibit various responses to impact suggests an advantage in combining more than one type of material in a panel. Mixing different materials in an appropriate sequence would make the best use of their corresponding properties and consequently enable the panel to be more energy absorbent.…”

supporting

confidence: 77%

“…Inspired by this design guidance, engineering hybrid panels containing more than one type of material is a reasonable approach. 13,14 One of the most studied approaches is the incorporation of woven fabrics in UD fabric panels. 9,15 Although a woven fabric alone does not provide desirable anti-blunt-trauma properties, this type of structure is useful in impeding the progressive failure of fabric plies when placed near the impact face of a panel.…”

mentioning

confidence: 99%

The structural effects on the impact response of ultra-high-molecular-weight polyethylene plain weaves

Zhou

Xiong

et al. 2020

This paper investigates the penetration and energy absorption mechanisms of ultra-high-molecular-weight polyethylene plain weaves with different fabric properties. Impact tests along with finite element (FE) analysis were used to study the impact response of the fabrics. In this research, the impacting projectile did not cause any fiber or yarn failure on the samples. It was found that structural parameters determine the yarn pull-out behavior and the softness of the resultant fabrics. Fabrics formed by loosely interlaced yarns tend to exhibit higher softness and less resistance against yarn pull-out. When the projectile velocity is not sufficient to initiate yarn pull-out, material softness determines the depth of the backface signature on the clay witness. This trend is more pronounced in a multi-ply fabric system than in a single-ply system; when yarn pull-out occurs, the projectile-slowing mechanism depends on the frictional force between the warp and weft yarns. Therefore, fabric softness becomes less important, and the yarn pull-out behavior of the fabric plays a predominant role in energy absorption. FE prediction showed that tightly woven fabrics exhibit a larger area of stress distribution and material deformation than those with severe yarn pull-out and, consequently, these tight fabrics tend to absorb more kinetic energy and sustain higher impact load from a projectile.

“…The number of plies was chosen in order to calibrate the ballistic test results with those provided by the manufacturer and with a previous study performed by the authors. 9 Fabric materials were cut to sample sizes of 0.305 Â 0.305 m 2 (12 Â 12 inches), and subsequently edge-stitched three times together with a 25.4 mm (1 inch) margin from the edges for easier handling. The edge-stitching does not significantly alter the ballistic performance.…”

Section: Target Materialsmentioning

confidence: 99%

Localized impact stress concentrations in soft armors due to microscale projectile edge geometries

Guo

Chen²,

Zheng

2018

Self Cite

Although extensive focus has been placed on the ballistic performance of projectiles with certain macroscale geometries and dimensions, the microscale geometries are not as rigorously standardized. The localized stress concentrations arising from microscale geometries introduce multiaxial and locally concentrated stress states within the constituent material of the soft-armor target, which can result in premature failure that is not predicted with existing models. In this study, the microscale edge/corner geometries of right circular cylinder (RCC) projectiles are varied, and their respective ballistic performance was determined via experiments to examine the effects of the localized stress concentrations. Target panels were examined post-mortem and the effects of these localized stress concentrations on the failure modes were quantified. Experiments results indicate that stress concentrations drastically reduce the ballistic performance of the soft armor targets, and the fabric targets appear to fail without significant strain energy absorption.