Scientists have developed a new lightweight, shock-absorbing football helmet system that effectively dissipates the energy from strong impacts and can better prevent brain injury.
To dissipate energy, a helmet typically has to deform, like the bike helmets crack in a collision. When a bike helmet breaks, it is absorbing "impulse" - a secondary effect of an initial force.
Impulse, which gives objects momentum, transmits kinetic energy through a system. It takes into account not just force, but also how long that force was applied.
The prototype called Mitigatium developed by researchers from University of Michigan in US, could lead to a lightweight and affordable helmet for players of the American football - a full-contact sport in which injuries and concussions are relatively common.
For head protection to be most effective against the speeds and weights of players on a football field, it has to block impulse.
Current helmets can not do this, and that is one of the reasons they are not very good at preventing brain injury.
"Today's football helmets are designed to prevent skull fractures by reducing the peak force of an impact," said Ellen Arruda, professor at the University of Michigan.
"But they don't actually dissipate energy. They leave that to the brain," Arruda said.
Scientists do not fully understand how a blow to the head translates to brain injury, but the researchers say impulse is a big factor.
Researchers studied the mechanical features of impacts and blasts and how helmets and other armour might be designed to do a better job protecting sensitive structures.
They built 2D mock cross-sections of materials that stood in for the brain and skull in various helmet shells.
Then they use a table-top collision simulator to test the different samples and compared how much energy was transmitted through to the brain-type layer in their helmet system and the status quo.
They used a high-speed camera to help them observe how the brain model deformed in both systems. In their experiments, the conventional helmet model did little to block impulse.
Mitigatium reduced impulse to just 20 per cent of what got through to the brain model in the conventional helmet. The prototype reduced peak pressure to 30 per cent.
The helmet is made of three materials. The first layer is similar to the hard polycarbonate that is the shell of present-day helmets. The second is a flexible plastic.
Together these substances reflect most of the initial shock wave from a collision - most of the initial force.
They also convert the frequency of that incoming pressure wave to a frequency that the next layer can dissipate by vibrating. This third "visco-elastic" layer has the consistency of dried tar.
The research was published in the Journal of the Mechanics and Physics of Solids.
This VTP award is an addition to a previous $34 million
award, for a total of $70 million on the VTP LRIP contract.
"We are honored to be the awardee of these prestigious contracts," said Cheryl Ingstad, business manager, Advanced Ceramics Platform - Defense, 3M. "The SPS program represents the highest level of lightweight technology to date. Our focus from the onset has been to meet the Army's stringent specifications for the SPS, and that will continue as we move into initial production. As a leading science company, 3M has deep expertise in advanced lightweight materials, which, combined with our proven production history, differentiates our defense offerings."
"3M is proud to be part of U.S Army's vision to be technologically superior while safeguarding borders, and the interest of the country," said Mr P T Mukund, Executive Director, Industrial Business Group, 3M India Limited. He added, "This contract is a testimony to the quality and superior protection that we can offer to our customer in India too.
The SPS will replace the Army's current personal
protective equipment (PPE) system. It is designed to defeat current threats while providing an overall weight reduction for soldiers compared to existing PPE. Both the IHPS and VTP began as research and development programs with multiple contenders.
Ceradyne has delivered more than 120,000 enhanced combat helmets (ECH) to the U.S. Army and Marine Corps since 2014. The ECH offers the highest protection level of any helmet in the U.S. Armed Forces inventory, even protecting against certain small arms threats. Ceradyne has also delivered more than 2 million hard body armor inserts to the U.S. Armed Forces to date.
For more information about soldier protection solutions provided by 3M, visit http://www.3M.Com/Defense [http://cts.Businesswire.Com/ct/CT?id=smartlink&url=http%3A%2F %2Fwww.3MDefense.Com&esheet=51450255&newsitemid=20161101005122 &lan=en-US&anchor=www.3M.Com%2FDefense&index=1&md5=309ea7505e5 f5ffa2776bafb190822f5 ] .
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