Fibrous Armor

Laible, Roy C.

doi:10.1016/b978-0-444-41928-6.50009-0

Cited by 14 publications

(4 citation statements)

References 27 publications

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“…Here, we generated strain rates from quasi-stationary up to 300%s -1 , and measured at most a sixfold increase in total energy absorbed by the web. Some studies have suggested that spider silk could increase work by slightly increasing total extension at high strain rates (Gosline et al, 1999;Laible, 1980), but we found no evidence of higher extension of silk measured at the whole-web level (Fig.5). At a given length, silk must therefore be stiffer at higher strain rates.…”

Section: Discussioncontrasting

confidence: 54%

Mechanical performance of spider orb webs is tuned for high-speed prey

Sensenig

Kelly

Lorentz

et al. 2013

Journal of Experimental Biology

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SUMMARYSpiders in the Orbiculariae spin orb webs that dissipate the mechanical energy of their flying prey, bringing the insects to rest and retaining them long enough for the spider to attack and subdue their meals. Small prey are easily stopped by webs but provide little energetic gain. While larger prey offer substantial nourishment, they are also challenging to capture and can damage the web if they escape. We therefore hypothesized that spider orb webs exhibit properties that improve their probability of stopping larger insects while minimizing damage when the mechanical energy of those prey exceeds the web's capacity. Large insects are typically both heavier and faster flying than smaller prey, but speed plays a disproportionate role in determining total kinetic energy, so we predicted that orb webs may dissipate energy more effectively under faster impacts, independent of kinetic energy per se. We used high-speed video to visualize the impact of wooden pellets fired into orb webs to simulate prey strikes and tested how capture probability varied as a function of pellet size and speed. Capture probability was virtually nil above speeds of 3ms -1 . However, successful captures do not directly measure the maximum possible energy dissipation by orb webs because these events include lower-energy impacts that may not significantly challenge orb web performance. Therefore, we also compared the total kinetic energy removed from projectiles that escaped orb webs by breaking through the silk, asking whether more energy was removed at faster speeds. Over a range of speeds relevant to insect flight, the amount of energy absorbed by orb webs increases with the speed of prey (i.e. the rates at which webs are stretched). Orb webs therefore respond to faster -and hence higher kinetic energy -prey with better performance, suggesting adaptation to capture larger and faster flying insect prey. This speed-dependent toughness of a complex structure suggests the utility of the intrinsic toughness of spider silk and/or features of the macro-design of webs for high-velocity industrial or military applications, such as ballistic energy absorption.

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Section: Discussioncontrasting

confidence: 54%

Mechanical performance of spider orb webs is tuned for high-speed prey

Sensenig

Kelly

Lorentz

et al. 2013

Journal of Experimental Biology

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“…High modulus and high tenacity being advantageous properties of armor fibers, Kevlar® represented a step change in performance, showing a strength 2.5 times that of nylon and an elastic modulus an order of magnitude greater. 4–6 In 1990, ultra-high molecular weight polyethylene (UHMWPE) was subsequently introduced to market by DSM under the brand name Dyneema®, meaning strong fiber in Greek. Dyneema® has certain strength and modulus advantages over Kevlar®, but the unique properties of each mean that they both feature in today’s soft armor market.…”

mentioning

confidence: 99%

Optimization of soft armor: the response of single-ply para-aramid and ultra-high molecular weight polyethylene fabrics under ballistic impact

Ralph

Baker

Archer

et al. 2020

Textile Research Journal

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Typical soft armor systems are constructed of multiple layers of a single fabric type. This empirical research sought to begin optimization of these systems through hybridization, sequencing dissimilar armor fabrics to maximize their ballistic protective performance, by first investigating single plies with a spectrum of properties to determine their behavior and response to impact. Eight individual plain weave fabrics with varying yarns and thread counts were manufactured from para-aramid and ultra-high molecular weight polyethylene (UHMWPE) yarns and physical and ballistic characterizations were conducted. The ballistic impact tests established the specific energy absorption (SEA) of each fabric across a range of impact velocities (340–620 m·s–1) and the transverse displacement wave velocity across the rear of the fabric was found using digital image correlation. Low cover factor ( Cfab) fabrics (0.74–0.84) consistently showed faster transverse wave speed than the high Cfab fabrics (0.84–0.96) for any given yarn type. The relative SEA of the fabrics varied dependent on both the impact velocity and number of plies impacted. It was found that lower Cfab fabrics had the highest SEA, critical velocity and transverse wave velocity. UHMWPE fabrics were not considered suitable for a woven hybrid system as they had a significantly lower SEA compared to all the para-aramid fabrics. Results indicate that a hybrid system, when considered as a theoretical spaced system, would benefit from higher Cfab fabrics as rearward layers. However, transverse wave results suggest the lower response of these fabrics may inhibit lower Cfab fabrics at the front of a combined hybridized system.

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“…The ability of a woven fabric to protect against bullets depends primarily on the mechanical properties of the yarn, such as the tenacity, tensile modulus, and toughness. However, Laible [7] demonstrated that "the relationship between the mechanical properties of a yarn and the ballistic resistance of a plied fabric from such yarn has never been established"; i.e., other factors may exist that influence ballistic performance. Generally, the energy absorption mechanism of soft armor depends on several additional factors, such as the weave pattern, the number of fabric plies, and the weave density.…”

Section: Introductionmentioning

confidence: 99%

Ballistic Behavior of Heracron<sup>&reg</sup>-Based Composites: Effect of the Number Multifilaments on High-Speed Projectiles

Lim¹

2013

MNSMS

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In this study, two Heracron ® woven fabrics, HT840-1 and HT840-2, were fabricated with different multifilament fibers, and their resistance to ballistic impact was investigated. For the same weight and number of plies, the HT840-2 fabric showed improved ballistic properties, compared with HT840-1; this result is contrary to the fiber and fabric properties. With the exception of the yarn's physical properties, this behavior can be explained in terms of the number of multifilaments, which strongly influenced the ballistic mechanism, i.e., a greater number of multifilament fibers facilitates energy dissipation from a high-speed ballistic projectile. In summary, establishing this optimal number of multifilaments is the key to optimizing the ballistic properties of any given fabric.

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Fibrous Armor

Cited by 14 publications

References 27 publications

Mechanical performance of spider orb webs is tuned for high-speed prey

Mechanical performance of spider orb webs is tuned for high-speed prey

Optimization of soft armor: the response of single-ply para-aramid and ultra-high molecular weight polyethylene fabrics under ballistic impact

Ballistic Behavior of Heracron<sup>&reg</sup>-Based Composites: Effect of the Number Multifilaments on High-Speed Projectiles

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Fibrous Armor

Cited by 14 publications

References 27 publications

Mechanical performance of spider orb webs is tuned for high-speed prey

Mechanical performance of spider orb webs is tuned for high-speed prey

Optimization of soft armor: the response of single-ply para-aramid and ultra-high molecular weight polyethylene fabrics under ballistic impact

Ballistic Behavior of Heracron&lt;sup&gt;&amp;reg&lt;/sup&gt;-Based Composites: Effect of the Number Multifilaments on High-Speed Projectiles

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Ballistic Behavior of Heracron<sup>&reg</sup>-Based Composites: Effect of the Number Multifilaments on High-Speed Projectiles