By Douglas Birch
Illustration by John Weber
Few modern structures are as ugly, ominous, or as seemingly vital as blast walls—the steel-reinforced concrete barriers erected around buildings to protect them from things that go bang in our age of uncertainty.
If you need a blast wall, how big should it be? How thick? The bigger and thicker the better, if your sole concern is stopping an explosion. But it turns out there is a price to be paid for what seems like perfect safety.
“If you make them too big and too thick, you can’t move them around, so you end up locking yourself in one place,” says K.T. Ramesh, director of the new Johns Hopkins Extreme Materials Institute (HEMI) at the Whiting School of Engineering and the Alonzo G. Decker Jr. Professor of Science and Engineering. “You develop a bunker mentality because you built a bunker.”
Large, heavy blast walls don’t just limit mobility. The bulkier they are, the more expensive they are to make, to move, and to tear down when they’re no longer needed. The Iraqi government claims that the blast walls the U.S. built in Baghdad helped cause $1 billion in damage to the city’s roads, sewers, and other infrastructure.
[Should] a barrier break up into small pieces, large pieces, or not break up at all? If it should break up, how can it do it in a way that limits damage and injuries?
Neither are these monoliths necessarily the best defense against an attack because they can make it more difficult for those behind them to see trouble coming and stop it.
Ramesh’s institute is using an array of sophisticated new analytical and digital tools to study how materials behave in what are called “extreme dynamic environments.” He is just one of a number of Whiting School engineers who have worked with the Department of Defense searching for ways to make tougher, lighter metals, polymers, ceramics, and other materials.
This basic research could lead not just to better blast walls but to more blast-resistant vehicles, buildings, and body armor.
Throughout the history of warfare new weapons have always demanded better armor—the stuff that absorbs and disperses the energy from an impact. Creating the stuff that other stuff is made of can be a slow process. The White House’s 2011 Material Genome Initiative found that it typically took decades for new materials to go from the laboratory to the market.
A major reason, the report said, was the traditional reliance on “scientific intuition and trial-and-error experimentation” in materials research. Instead, the report found, materials development and testing should move faster into computer simulations, where testing can be done in virtual space with faster, more powerful computers running sophisticated new software.
The goal: to double the speed and cut the costs of discovering, developing, and deploying new high-tech materials needed to strengthen national security, energy security, human welfare, and industry. A number of Whiting School researchers are working toward that mark, with an emphasis on national security, under military grants for unclassified research.