Physics Central
When today’s soldiers enter combat, they’re better protected from explosions than the military personnel of any previous war. Ultra-strong helmets shield them from the flying shrapnel of homemade bombs; high-tech cushioning cradles their skulls during sudden impacts with the ground. But because modern soldiers are surviving explosions that would have taken the lives of Vietnam-era infantrymen, army hospitals are seeing a rise in a particularly painful war wound—traumatic brain injury (TBI).

TBI can range from a simple concussion to damage with long-term effects, including impaired cognitive abilities and even anxiety and depression. New research is helping to explain how those injuries come about, potentially pointing the way to helmet designs to reduce brain damage. Using code originally designed to simulate how a detonated weapon rattles a building or tank, physicists at Lawrence Livermore National Laboratory in California and the University of Rochester in New York modeled an all-too-real situation: a 5-pound bomb exploding 15 feet from a soldier’s head. Their goal was to understand the effects of the high-speed shock wave that follows an explosion.