Can a Truck Equipped With Airbags and V-Shaped Hull Prevent Roadside Bomb Casualties?
By Grace V. Jean
BALTIMORE — Roadside bombs have caused 80 percent of the casualties in Iraq and Afghanistan. During a single week last month, there were 400 attacks on U.S. forces across Afghanistan and of those 250 were improvised explosive devices, or IEDs, said Gen. George W. Casey, chief of staff of the Army.
Newer trucks with V-shaped hulls can deflect the force of those explosions, but they are not completely immune to the effects of a blast.
“Acceleration is the most significant casualty-producing mechanism in our combat vehicles when hitting improvised explosive devices,” said Brig. Gen. Michael Brogan, commander of the Marine Corps Systems Command.
Vehicles caught in a bomb blast experience two acceleration events: One is in an upward direction after the blast goes off. Its duration is between 40 to 50 milliseconds. The second event, when the vehicle returns to the ground and stops abruptly, is analogous to an automobile accident and lasts roughly 200 milliseconds.
“That first 40-millisecond event is causing the majority of the casualties,” said Brogan, who challenged industry attendees at a National Defense Industrial Association conference to design a survivability capsule with a seating and restraining system that could “cocoon” an occupant and decouple the vehicle’s acceleration from the force that is delivered to him.
“People say automotive airbags can’t do that because they operate in that second event, that 200-millisecond event. Does it, or is that the way we’ve done that?” questioned Brogan. “In our litigious society, have we dumbed down our airbags, have we slowed their speed of deployment to prevent the vehicle occupant from having his nose broken or glasses broken? Could we tune these up to get closer to that 40-millisecond event, recognizing that we would be accepting of minor injury to prevent much more serious injuries?”
Brogan also pointed out that the Corps lacks modeling tools to simulate those events against vehicle design drawings to understand both what occurs to the vehicle and what happens to the occupants inside of it. “We need the same kind of blast tools like we have with ballistic tools,” he said.