News Release

Using noise to cancel noise

Peer-Reviewed Publication

Virginia Tech

(Blacksburg, Va., July 18, 2000) -- Ricardo Burdisso refers to his work as an "enjoyable journey" when he is able to use his engineering skills to develop a new technology that could benefit society.

The Virginia Tech associate professor of mechanical engineering is currently in the middle of such a journey.

The voyage started about a decade ago when he participated in a research project that illustrated noisy jet engines could actually be silenced with, ironically, the use of noise. The technology appeared to be a partial solution to airport noise pollution; one of the problems from industry's standpoint was the cost of the technology.

As Burdisso explains the problem, "Consumers are concerned about the environment, and one of the critical problems with aircraft is the noise pollution. The growth of the aircraft industry is limited by the noise pollution. Reagan Airport's limitation on aircraft flying during the night hours is a good example of the restrictions placed on the industry."

When Burdisso and his colleagues first looked at actively controlling engine noise, using a method to cancel noise by electronically generating anti-noise signals, they discovered that industry would not buy into the technology.

Industry management was concerned primarily about the increase in the weight and the cost of the engine since the researchers were actually proposing to add acoustic energy or anti-sound to the system. The additional weight would increase fuel consumption, an unappealing thought to the aerospace companies.

Burdisso recalls coming to the university's Vibrations and Acoustics Laboratory (VAL) one Saturday, looking at the experimental engine, and having a brainstorm. He thought about his idea during the next six months, and then decided to test his theory in the lab. VAL research associate Jerome Smith built Burdisso's new system, incorporating a passive approach to reduce the noise.

Simply explained, this new passive control approach "works by taking some of the acoustic energy from one part of the engine to cancel sound in another part," Burdisso says. By using the existing energy, no additional weight is added to the engine, eliminating industry's concern about additional fuel consumption.

Burdisso shared the concept of the new engine with a colleague at NASA, sending him a representative one page viewgraph. The next day he received a positive response from the space agency, and it provided him with the money to repeat the experiment. The second time produced better results, and he and Smith filed for a patent on their new engine.

The mechanical engineers presented their new work to industry, and this time the response was positive. Honeywell Engine and Systems (formerly AlliedSignal) tested the concept in one of its full production engines, and B.F. Goodrich subsequently licensed the patent while it remains in the application stage. B.F. Goodrich is discussing developing the technology during the next three years.

"This research could make an impact and be beneficial to society," Burdisso says. "Seeing this idea go on to implementation in a product is a journey I really enjoy."

Burdisso's love for research began as an undergraduate engineering student at the National University of Cordoba in Argentina. Born the youngest son of three siblings, he was the only one to attend college. His two older brothers joined his father's manufacturing company, a business they continue to manage after their father's retirement. When Burdisso was a sophomore in college in 1979, he became involved in the materials research lab, investigating the structure of materials to identify potential failures.

At that time, few undergraduates worked in research labs. "There might have been 10 of us. This work aroused my scientific curiosity," he says, and he soon determined that he wanted to continue with research and development ideas that led to practical solutions.

His career at Virginia Tech has taken some interesting turns. He applied to the College of Engineering as a graduate student because of a research project he undertook while still in Cordoba. Apparently a nuclear power plant was built unknowingly on a seismic fault. Burdisso joined the team that performed a structural analysis of the facility; the team included M.P. Singh, an engineering science and mechanics professor at Virginia Tech who is an expert in structural dynamics and earthquake engineering.

After the project was finished, Burdisso moved to Blacksburg to obtain his doctorate under Singh's advisorship. After he obtained his Ph.D. in 1986, he spent the academic year as a visiting assistant professor in the Department of Aerospace and Ocean Engineering. For the next two years, Burdisso worked at Aerostructures Inc. of Arlington, Va., but he longed to return to laboratory research.

When Chris Fuller, a mechanical engineering (ME) professor and the director of VAL, had an opening for a research scientist in the area of noise control, Burdisso applied successfully for the job. Three years later in 1992, he moved into a tenure track ME faculty position, earning his associate professor status in 1996.

Some of his other research work includes sctive flow control, attenuation of sound from structures, and vibration isolation in vehicles. In total, Burdisso is responsible for $2.4 million in research contracts since 1992.

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PR Contact: Lynn Nystrom tansy@vt or 540-231-4371


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