Grad student Phillip Mulligan is trying to make improvised explosive devices more powerful with the idea of eventually making them less deadly.
“We are trying to perfect our version of the explosive device,” says Mulligan, MinE’07, now pursuing a master’s degree with an emphasis in explosives engineering. “We are trying to create the best device we can, so we can learn how to develop the best armor possible.”
But first, he needs to know just how powerful the little bombs can be and what kind of damage they can do. That’s why he’s making his own.
Out at a small quarry at the Missouri S&T Experimental Mine, Mulligan blows up the IEDs he made and captures the explosions with high-speed cameras. For security reasons, he won’t let anyone take photos of the small bombs or video them, but he’s happy to talk about his research.
Mulligan’s IEDs are made of PVC, copper and, of course, explosives. When detonated, the copper plate explodes into shrapnel that flies everywhere. The main slug, though, travels at 6,000 feet per second in a pre-determined direction.
The objective here is to shoot the main slug at an 1,800-pound, three-inch-thick sheet of steel that Mulligan has placed 20 feet away from the IED.
By way of demonstration, Mulligan ties one of his IEDs to three wires that suspend it in the air in front of the target. Then he instructs onlookers, all wearing safety helmets and ear plugs, to take cover with him behind a protective barrier about 200 feet away.
Mulligan shouts “Fire in the hole!” three times. Then a terrifying explosion occurs. Those behind the barricade wait for tiny pieces of hot copper to stop raining from the sky before returning to the blast site.
The IED is gone; there’s nothing left of it. The copper shrapnel on the ground around the site is larger than the small pieces that were falling from the sky near the shelter. “This is something we want to study,” Mulligan says. “How big is the shrapnel and why? We need to see how it behaves.”
Mulligan uses high-speed cameras to capture the explosions. One of the cameras, which is protected by a panel of special glass, shoots 10,000 frames per second. The images can be used to determine the speed and behavior of projectiles.
Mulligan’s research advisor is Jason Baird, PhD MinE’01, an explosives expert who is an associate professor of mining engineering at S&T.