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Lightweight aluminum v. a hand grenade, who wins?

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Concrete and steel are the materials of choice when building buildings and vehicles that will protect soldiers from enemy fire. But a group of Norwegian researchers are testing another option: lightweight aluminum panels that can be filled with densely packed dirt, gravel, sand or any other nearby substance to provide protection without adding a lot of weight to a military's vehicles or structures, according to a recent report in the Norwegian research magazine Gemini. The aluminum panels are designed to fit together and any substance used to fill the cavity could be emptied out of the bottom of the panel before it is moved.

The Norwegian University of Science and Technology's SIMLab (Structural Impact Laboratory) also searching for a substance that can absorb the pressure exerted on the underside of a tank by a landmine explosion without adding a lot of weight to the vehicle. One proposed option is developing plates made from aluminum foam, which could absorb the impact of a bullet or piece of shrapnel and keep it from shredding the soldier on the other side of the armor. Such foam, basically a porous version of aluminum, is being developed by a number of companies, including Alcoa, Inc. in Alcoa Center, Pa., and Toronto's Cymat Technologies Ltd. and would be nonflammable and recyclable.

SIMLab researchers, working with the Norwegian Defence Estates Agency (NDEA), a branch of the Norwegian Defense Ministry responsible for the Norwegian camps and compounds involved in international operations, say they have tested the aluminum panels in a full-scale explosion that was equivalent to four tons of TNT detonated from 394 feet (120 meters) away. The target of that explosion, a container protected by aluminum panels received just minor damage, Gemini reports.

Photo courtesy of SIMLab

Larry Greenemeier is the associate editor of technology for Scientific American, covering a variety of tech-related topics, including biotech, computers, military tech, nanotech and robots.

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