Defense Technology International - July 2007 - (Page 10)

SCIENCE WATCH MICHAEL DUMIAK POWER SHIELD Electromagnetic armor for land Ballistics Research Laboratory, once cut through 3.4 meters (11.15 vehicles remains a laboratory ex- Germany’s Fraunhofer Institute for ft.) of steel armor with such a weapperiment, but proponents say it High-Speed Dynamics, United De- on. But the copper composition could become an effective means fense Industries (now part of BAE of protecting armored vehicles from Systems) and Israeli researchers are makes the plasticized jet vulnerable. some of the most lethal projectiles among those experimenting with Within an electromagnetic ﬁeld, a charged particle passing through the material. on the battleﬁeld. Electromagnetic armor features two charged plates is subject to John Jude, a chemical engineer who conducts research on electro- two oxygen-free, high-conductiv- the Lorentz force, which causes the magnetic armor for the Office of ity copper plates or tiles separated particle to veer perpendicularly to Naval Research and Hy-Tek Manu- by insulators like ceramic or glass. the field. Electromagnetic armor facturing Inc., Sugar Grove, Ill., says One plate has a negative charge, isn’t meant to stop the jet, but to the material uses basic principles the other a positive charge. The break it up and thereby reduce its of physics—speciﬁcally the Lorentz plates or tiles would be installed penetrating ability. The copper jet crashes through the first force–to prevent rocket-procharged plate and into the pelled grenades (RPG) and second. This bridging link explosively formed projecbetween the surfaces sparks tiles (EFP) from penetrating the magnetic ﬁeld. a vehicle. “We can see the particuThe material is both lation almost instantly as it promising and problematic. penetrates the second plate On one hand, it may prove and creates the electrical to be a real life-saver by connection that discharges protecting vehicles from the capacitor,” Jude says. weapons like EFPs, which, “High-speed photography though based on old techof the jet shows that it’s an nology, are taking a toll on undulating entity. It looks U.S. and coalition forces in like thick sections followed Iraq. Electromagnetic armor by thin sections followed by is also lightweight, weighthick sections—almost like a ing about half as much as caterpillar.” conventional steel, reactive A Marine gunner on an armored vehicle scans The thin sections, which or composite armor. for threats during a raid in Iraq. Researchers are as narrow as 1 mm., On the other hand, elec- say electromagnetic armor can protect crews are highly affected by the tromagnetic armor is huge- from EFPs and other weapons. Lorentz force. In tuning the ly expensive, at least right now. One published source esti- on top of a vehicle’s roll-hardened field with different voltages and mates it would cost $500-1,000 per steel armor, which would provide plate distances—one optimal setlb., with typical applications requir- the main ballistic protection. As ting appears to be 10 cm. between ing about 2 tons per vehicle. The Jude explains, electromagnetic ar- the plates—Jude and his researchers cost, however, will probably drop mor depends on the warhead of a were able to cut the jet’s penetratshaped round creating a bridge be- ing power into roll-hardened steel with commercial production. armor by slightly more than half, The biggest problem is that the tween the two surfaces. EFPs gain their deadly perfor- from 15 in. with no electromagnearmor requires a large amount of electricity to activate it—so much, mance from a concave, bowl- tism to 7 in. Jude claims additional in fact, that its use may not be feasi- shaped copper lining. Copper is experiments by researchers reduced ble until all-electric combat vehicles ideal because of its malleability steel penetration to less than 4 in. An optimized system of electrowith their own power-generating and the shape it takes when ﬁred capabilities become commonplace. from a launcher. When the charge magnetic armor would still mean veElectromagnetic or “dynamic” ﬁres, the concave apex of the lin- hicles need a minimum thickness of armor has been considered for the ing is propelled to the front and the steel to survive. In Jude’s best-case U.S. Navy’s new CVN-78 aircraft car- lip of the lining trails behind. The scenario so far, the ideal thickness rier. Applying it to a land vehicle, lip is often described as a molten would be 4 in. Still, Jude is bullish on the proshowever, is an entirely different or plasma stream. Jude says it is actually plasticized metal that, while pects. “This works and it’s viable,” challenge. Nevertheless, work continues still somewhat solid, acts as a ﬂuid. he says. All that remains to be seen is on making the concept viable. The The front of the copper jet can slice quest for electromagnetic armor through roll-hardened steel armor. whether a real-world system of arhas a long history, dating back Researchers at Lawrence Livermore mor protection can be coaxed from to the early 1970s. The U.S. Army National Laboratory in California the lab-based technology. I 10 DEFENSE TECHNOLOGY INTERNATIONAL JULY/AUGUST 2007 USMC LANCE CPL. RYAN C. HEISER www.aviationweek.com/dti http://www.aviationweek.com/dti

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Defense Technology International - July 2007

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