Beyond the blast: Soldier head protection research moves from ballistic to shock wave threats
December 3, 2012
By T'Jae Gibson, Army Research Laboratory, Public Affairs Office
ABERDEEN PROVING GROUND, Md. (Dec. 3, 2012) -- Ballistics and material research experts told Army senior leadership on Friday that novel approaches to basic research are advancing new findings in Soldier head protection solutions against blunt impact and even shock waves.
Dr. Shawn Walsh, Agile Manufacturing Technology team leader of the U.S. Army Research Laboratory's (ARL's) Weapons and Material Research Directorate, told Gen. Dennis Via, commander of the Army Materiel Command in Huntsville, Ala., that its multifold approach goes beyond ballistic threats.
"Historically, all U.S. helmets have been primarily designed for ballistic fragment threats not blast events. Our approach addresses the integration of three tremendous challenges -- providing ballistic protection from fragments, 9mm bullets and small arms projectiles, increased blunt impact protection and blast protection," Walsh said. "Collectively, tools and technologies that address all of these will allow for insight and the ability to design mitigation strategies for overall improvement and balancing of head protection from multiple threats."
Gen. Via's two-day intensive tour at Aberdeen Proving Ground covered ARL, Chemical Materiel Agency and Communications Electronics Command game-changing technology concepts to transition approaches and how Aberdeen Proving Ground's assets are helping to define the Army's and the Mid-Atlantic region's technological edge.
Inside the Composites Laboratory, researchers told Gen. Via about ARL's novel experimental characterization of a novel syntactic foam which (in lab-scale testing) has shown significantly more effective ability to reduce blunt impact. Collaborative efforts are planned with Natick Soldier Research, Development and Engineering Center to test the foam in an actual helmet system in 2013.
The use of this foam, a collection of small glass "microspheres" that locally crush under impact loads which in turn results in the dissipation of significant amounts of impact energy, evolved from a broader ARL partnership with industry and academia to develop helmet technology that helps military and industry modeling and simulation and medical communities understand how to develop a improve head protection.
In 2010, ARL teamed with Project Manager Solider Protection Individual Equipment, and Natick Soldier Research, Development and Engineering Center (NSRDEC) to develop the Enhanced Combat Helmet, and to explore application of the novel materials and processes for lighter weight alternatives to the currently fielded Army Combat Helmet.
As part of the research effort, ARL scientists pioneered a molding process to pre-form a helmet from the thermoplastic material. The unique pre-form methodology has transformed the current U.S. industrial base, considering the U.S. ballistic helmet material and manufacturing has not changed significantly since Kevlar was first introduced in the early 1970's.
The pre-form assembly machine is the only one of its kind, Walsh said, and it combines layers of the material into helmet shells. Its primary benefit to Soldiers: they're lightweight.
"The Army has historically been an early adopter of new materials and concepts in its effort to provide the U.S. Soldier with the best possible protection against known threats," Walsh said. ARL's "pioneering use" of these new, man-made synthetic polymer fibers that replaced steel in helmets is a current example.
Combat helmet advancements are now moving toward protection solutions against shock wave impact, ARL researchers said.
Earlier this year, ARL launched a multi-scale research effort to understand how blast waves transfer energy through head protection systems and to what degree this energy results in injury to Soldiers' brains. Partnering on this effort are the University of Nebraska at Lincoln, University of Pennsylvania, Columbia University and Duke University.
ARL researcher's efforts are focused to better understand axonal injuries and to that end, they have developed a 3-D fiber-informed finite element model of the human head in order to provide physics-based predictions of tissue and axonal damage. Modeling the axonal injury that occurs in the brain provides a means to relate an insult or injury from a ballistic event, football tackle or blast wave, for example, to a cellular injury mechanism.
"We created a novel algorithm that reads in every single one of the fibers from the Diffusion Tensor Imaging data and assigns the elements in the ARL-developed FE model an average fiber direction based on the fibers that cross/traverse that element," said Amy Dagro, a research scientist. "Since everyone's brain is "wired" differently, everyone has a different structural network and different fiber tractography so it is important to take this into consideration when trying to predict injury."
High performance computers within ARL's Defense Supercomputing Resource Center enable advanced capabilities to run simulations to capture, computationally, the way the brain moves inside the skull under event blasts since it is able to perform massively parallel finite element simulations with millions of elements.
"No protection solutions have been fully developed with the purpose of safeguarding the Soldier's brain from mechanical loading of a shock wave. We're still trying to understand which part of the blast wave we need to protect against and what level of the mechanical loading results in injury and neurocognitive deficits like memory loss, mood swings, insomnia, etc.,"
ARL is an invited Integrated Product Team (IPT) member of the NSRDEC's HEaDS UP Program, the largest future head protection program in the Army. This provides a direct path for early and continuous technology transfer and feedback with key stakeholders, users and decision makers, Walsh said.
"Redundant research is thus avoided by jointly identifying key technology gaps and then assigning core competencies from ARL, NSRDEC and their industrial and academic partners to systematically address these technology gaps. The result is a far more complex, comprehensive and rapid means of identifying and maturing critical technologies and reducing risk as the head protection concepts move to PM Soldier assessment," he said.
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