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February 1997



First full-powered smart material developed

Department researchers are involved in an effort that has produced the first fully functional smart material.

The government/industry/university team has produced a "smart skin" for underwater vehicles that actively absorbs sound for acoustic quieting. Initially developed to reduce a submarine's echo from threat sonar, the technology can be adapted to reduce sound in aircraft cabins, automobiles, tractor cabs and other places where sound reduction is wanted.

Smart materials involve devices that adapt to the mission requirements, such as airplane wings changing shape during flight to accommodate changes in operating conditions; or components of a space station self-repairing when damaged.

Researchers from many disciplines have been working on various aspects of smart materials since the mid 1970s, according to Professor Doug Lindner, who along with Professor Fred Lee, is serving as a principal investigator on the project. "Advances have included miniaturized sensors, actuators and electronics devices that get embedded throughout the material," he said. "However, until this project, no material had actually been fully powered. To make these materials do anything, large amounts of raw power are needed. This requires miniaturized power electronics devices that are capable of functioning at low temperature."

Expertise in miniaturizing the power supply to fit in the smart material came from the Department's Virginia Power Electronics Center (VPEC) and alumnus Dan Sable (Ph.D., '91) of Virginia Power Technologies, Inc., a Blacksburg start-up firm.

"We had to try to process a lot of power with very small components and deliver that power at very high frequencies," Lindner continued. "Our final design is very similar to taking a 50W stereo amplifier and shrinking it down to a 3- by-3-by 1/2-inch box."

"Our team designed and built the first prototype of the basic material, immersed it in water and successfully tested it," Lindner said. "We achieved significant echo reduction. That was the first smart material ever built that incorporated the power processing," he said. The team is now developing an improved design that will optimize performance of the material.

Lockheed Martin is the prime contractor on the project. Other partners include Signals and Systems, Inc., Active Signal Technologies, AVX, and the Naval Research Laboratory. The project is funded by DARPA and Virginia's Center for Innovative Technology (CIT.) Graduate students on the project include Greg Zvonar, Jiyuan Luan and Yuqing Tang. Troy Schelling at Virginia Power Technologies is also involved.


The Bradley Department of Electrical Engineering
Virginia Tech

Last Updated, May 5, 1997
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