ARMY AL&T
Advances in Helmet Testing Modeling of blast impact is in itself an area of extensive study. Different head- forms are suited to different blast tests in the laboratory. Scientists are working on a matrix of head forms, as scientists elsewhere develop metrics for injury.
“There’s not a lot of consensus on what the metrics are that we should be gath- ering,” said Dr. Dixie Hisley of ARL.
When a projectile hits a Soldier’s helmet, it deforms inside as it absorbs the energy, creating “helmet backface deformation.” The absorption of energy typically results in a bulge that could grow two to three inches or more toward Soldiers’ heads, which equates to “the potential for a pretty good impact on a Soldier’s head,” Hisley said.
But inside the helmet, there may be 1/2 to 3/4 inch between the helmet and the Soldier’s head. “What we at the ARL would like to do is come up with the one to two experimental techniques that would allow us to replicate and measure this phenomenon very accu- rately,” Hisley said.
Ideally, scientists should be able to correlate the velocity of impact, force applied, and the area of contact with the metric for injury, she said, using a method developed at ARL called Digital Image Correlation. “That’s the area that we should really be interested in: What available energy is going into the Soldier’s head?”
Next Steps The PEO Soldier Head Protection Summit sought to establish a body of experts from the academic, sports, defense, and medical communities to focus on the prevention and mitigation of head injury from blast, ballistic, and impact threats to the head. The follow-on is an Integrated Concept Team to develop solutions and improve Soldier head protection from threats encountered in combat conditions.
34 APRIL –JUNE 2011
The Generation II Helmet sensor will expand the data gathered in theater by recording both linear and rotational accelerations. (U.S. Army photo courtesy of PEO Soldier.)
“The experts have identified where we need to learn: a valid mathematical model of blast-induced TBI,” Leggieri said. “We’ve got lots and lots of models of traumatic brain injury. We don’t have any validated models.”
Through the Johns Hopkins University Applied Physics Laboratory, an expert panel is working to develop criteria for valid models, including capabili- ties, state of the science, validation to date, and availability to the DOD community. Validated models will be independently reviewed and, ultimately, submitted to the Assistant Secretary of Defense for Health Affairs for approval.
“This brings some standardization. It brings some assurance that whatever crite- ria are being used by DOD, those criteria are the best available,” Leggieri said. “We all have the same objective in mind. We want to protect the warfighter.”
Leggieri’s office, at https://blastinjury
research.amedd.army.mil, seeks to be
a clearinghouse for blast injury research information. Gilman’s presentation at the Army Science Conference is available at
http://www.armyscienceconference. com/pdf/Tue/Gilman.pdf.
MARGARET C. ROTH is the Senior Editor of Army AL&T Magazine. She holds a B.A. in Russian language and linguistics from the University of Virginia. Roth has more than a decade of experience in writing about the Army and more than two decades’ experience in journalism and public relations.
ROBERT E. COULTAS is the Army AL&T Magazine Departments Editor and an Army AL&T Online Editor. He is a retired Army broadcaster with more than 35 years of combined experience in public affairs, journalism, broadcast- ing, and advertising. Coultas has won numerous Army Keith L. Ware Public Affairs Awards and is a DOD Thomas Jefferson Award recipient.
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