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What’s new in ballistic materials

January 11th, 2021 / By: / Feature

Blast wave and fragments require a different kind of protection. Photo: Medium.com.

The next leap in these protective technologies is on the horizon. 

by Debra Cobb

For the past few decades, para-aramid fibers and UHMWPEs (ultra-high molecular-weight polyethylene) have been the standard bearers in ballistic textiles. But the changing nature of warfare and the need to increase mobility while improving protection are challenging the industry to step up the pace of innovation.

Raw materials suppliers DuPont Co., Honeywell Intl. and Teijin Ltd. have responded by improving their high tensile-strength ballistic fibers, working in collaboration with the textile manufacturers to create lighter weight fabrics that do a better job at blocking damage from high-power rifles, IED fragments and backface trauma.

High-tensile strength fibers evolve

The latest iteration from DuPont Kevlar® is Kevlar XP K520 for soft armor, according to Joe Hovanec, DuPont Kevlar global tech leader. It consists of layers of fibers in a +45°/–45° orientation that provide the required stopping power to address standard ballistic threats in a flexible solution with fewer layers and stitching, reducing labor and material costs.

Teijin’s recently-introduced high-tenacity Twaron® Ultra Micro 550f1000 yarns are designed for fragment-resistant vests. The micro filaments offer more surface area, increasing the stopping power of the fabric, while creating a softer, more comfortable ballistic material.

Honeywell’s Spectra® gel-spun UHMWPE fiber continues to be their workhorse, used in the Spectra Shield® 6000 composites series. The latest introduction, Spectra Shield 6166 for hard body armor, provides the highest energy adsorption for high-power rifle or high-energy threats.

DuPont Tensylon®, a UHMWPE tape, exhibits “upper echelon” ballistic performance in helmets, plates and ballistic vehicle liners, according to Hovanec. New developments are expected in the Tensylon portfolio next year.

Protecting the extremities

While vests and hard body armor protect the vital torso area, more attention is being given to protection for the extremities and pelvic area, which are particularly vulnerable to IEDs.

Woven fabrics of Dupont Nomex® meta-aramid fiber, as well as Kevlar, are being developed for use in tactical uniforms. 

“Comfort is a significant issue,” says Hovanec. “Combinations of fiber and weaving techniques protect against fragments and blast debris, which result in infection and multiple surgeries.”

Continuous filament para-aramid knits offer comfort and mobility in next-to-skin garments. TenCate Protective Fabrics’ Ballistic Knit interlock is currently used by the U.S. Army in their protective undergarments.

In Northern Ireland, a company called Vikela Armour is prototyping a new type of body armor made from multiple materials, including Kevlar and carbon fiber. The lightweight material is engineered into a suit that covers the whole body, offering improved protection from IED-driven shrapnel.

IEDs have been a major cause of soldier injury in the Middle East. Photo: army.mil. 

Tex Tech Industries, a global technical textile manufacturer based in Maine, employs felting and needle-punch in their Core Matrix Technology, which loosely locks down layers of ballistic materials with Z-directional staple-length fibers. Their latest iteration for combat shirts and pelvic protectors has been developed to meet current specs with 20 percent less weight.

“This gives us the opportunity to provide additional ballistic protection to other parts of the body and protect the soldiers’ extremities against fragmentation from IEDs and blasts at lighter weights while not jeopardizing the soldiers’ mobility,” says Eoin Lynch, the company’s executive director of sales and marketing.

Creating body armor’s next super-textile

Scientists continue to be intrigued by the potential of graphene in ballistic protection. Reported to be many times stronger than steel, graphene’s high strength-to-weight ratio makes it a desirable as a protective material. 

However, research in 2014 by associate professor Jae-Hwang Lee and other faculty at the University of Massachusetts Amherst was unable to precisely quantify the intrinsic dynamic qualities of graphene due to the effects of aerodynamics on its deformation process. Lee’s latest research, “Intrinsic Dynamics and Toughening Mechanism of Multilayer Graphene upon Microbullet Impact,” was published in 2020 in Applied Nano Materials.

The dynamic response of materials is related to their speeds of sound, and graphene’s speed of sound is exceptionally fast. The new research, performed in a vacuum with microbullets, demonstrated approximately 300 percent higher energy delocalization performance due to the unrestricted fast deformation of the multilayer graphene.

Since the purpose of lightweight body armor is to distribute the impact energy of a projectile across as large a region as possible, graphene’s ability to distribute this kinetic energy at high speed before fragmenting is impressive.

“The extraordinary mechanical characteristics of graphene motivates the next generation of technology, which includes ultra-strong and lightweight composites, as well as protective coatings,” says Lee.

He concludes, “Our findings provide a new perspective on the design of nanomaterials for a wide range of applications from body armor to aircraft and spacecraft, where physical damage can be caused by high velocity impacts at a wide length scale.” 

Taking a different approach, David O’Keefe, president and CEO of Advanced Fabric Technologies LLC (AFT), believes that the next iteration in ballistic protection will control surface area to change the geometry and properties of protective materials.

“It’s difficult for fabrics to compensate for ballistics,” he believes. “Enough layers of anything will protect you; but current materials are not efficient.” AFT’s custom-designed Xtegra™ auxetic yarns and fabrics offer protection from blast, ballistics and flame. Auxetic materials get thicker and stronger when stressed or stretched.

O’Keefe is also looking at shape metal alloys, which can move, constrict and carry current to enhance the functionality of armor. The company is in the process of developing a “reactionary level of protection, where the surface area reacts to pressure or acoustics.”

Progressing with partnerships

Research and development of ballistic technologies is a slow process, despite efforts by the military, academia and private enterprise. With lives at stake, the complexities of testing and fear of failure are formidable roadblocks.

DuPont is continuing to work on a broad platform of new advanced materials. “It’s a market-based approach, working with military and law enforcement globally to determine what’s needed by end users as new threats appear,” says Hovanec. “It’s not only the development of the fiber, but how to transform it into an end product, working with different manufacturing partners and testing with the U.S. military.”

“Cost is always an issue,” O’Keefe says. “We are not yet approaching the DoD [Dept. of Defense]; we’ll work on the civilian side first. … The technology is there. We need to put it together to meet the needs of weight, cost, efficiency and comfort. With the right partners, we could see prototypes for testing next year.”

Debra Cobb is a freelance writer with extensive experience in the textiles industry. She is a regular contributor to Advanced Textiles Source.