Waves due to explosive explosions cause brain damage even when there is no direct impact on the head area

New research on the effects of wave explosions can help deepen understanding of head injury and improve the design of protective helmets for soldiers.

With the use of hydrodynamic computer models, Willy Moss and Michael King, scientists at the Lawrence Livermore National Experimental Center, have discovered that waves caused by non-fatal explosions are sufficiently effective. to the skull folds damage the brain even if there is no direct impact on the head area.

Craniofacial injury (TBI) is the result of mechanical weight on the brain, often not accompanied by cracks, fractures in the skull and leaving complex, long-term symptoms for humans.

Traumatic injuries in people are often caused by direct impacts on the head area in traffic accidents and sports activities. Craniofacial injuries also appeared in soldiers participating in combat and affected by explosive waves. The current armor has significantly reduced trauma to soldiers in explosives attacks, however, the low mortality rate is accompanied by an increased incidence of traumatic brain injury.

There have been in-depth studies of the effects on the head region, for example in a car accident, in which way a traumatic brain injury will occur. But the brain injury that originates from the explosive wave is not associated with the effect on the head area is still a mystery to the scientific world.

To find the answer, this research group uses three-dimensional hydrodynamic models to demonstrate that the direct action of the vapor waves on the head region causes buckles on the cortex, producing weight. mechanics in brain tissue are similar to cases of injury, even when the explosion pressure is only as low as +1 bar.

Army's Advanced Combat Helmet replaced the old Personal Armor System for Ground Troops helmet. Kevlar shell helps protect soldiers from bullets and other agents, smaller hat edges help improve hearing and vision. (Photo: © US Army)

Specifically, the research team has shown that the wave caused by the explosion affects the brain in a completely different way than the direct effect.

'Waves from the explosion through the skull are like a roll running through dough,' said King, a survey officer at Lawrence Livermore National Experiment Center.

Simulations show that the skull is only deformed about 50 microns (equivalent to the width of a hair), but 'this is big enough to cause the weight to destroy potential in the brain,' Moss said. .

Due to the explosive wave and impact directly affecting the head in different ways, armor systems designed to preserve soldiers from projectiles and other impacts may not be suitable to protect them first. Slightly explosive waves.

Scientists have studied how the protective caps and their anti-shock systems affect the mechanical weight caused by waves in the brain.

'The possibility of explosive waves causing brain injury is important for treating trauma and improving armor design for soldiers,' Moss said.

Blackman adds: 'By comparing the effects of explosive waves on the head and the effect of direct impact, we will understand the different mechanisms of damage as well as their destructive power to a person. soldiers, and from there design a best helmet for soldiers. '

Detailed results are published in Physical Review Letters online on August 26.