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Southwest Research Institute receives $1.7 million to develop smart materials system

San Antonio -- January 28, 2004 -- The Defense Advanced Research Projects Agency has awarded $1.7 million in contract funding to Southwest Research Institute® (SwRI®) to develop a novel, wireless, sensor system for crack detection and monitoring in critical turbine engine components. The award is part of the technology development phase of DARPA's Prognosis program, which aims to provide field commanders with the ability to forecast, adaptively manage and use high-value military assets to the limits of their current capability.

Sensors for monitoring the damage state of turbine engine components are crucial to forecasting remaining life and managing assets in the field. Current indirect methods of crack sensing by monitoring the dynamic response of turbine shaft and blade-tip displacements have limited reliability for crack detection. Direct monitoring of cracks in turbine discs is hampered by the harsh thermal and stress environment of a jet engine.

"Our goal is to create smart materials that are capable of sensing their own state of damage using distributed thin-film magnetostrictive sensors integrated onto a component's surface near fracture-critical locations," said Program Manager Dr. Stephen Hudak, an Institute scientist in SwRI's Mechanical and Materials Engineering Division.

Ultrasonic waves will be periodically injected into the component to detect cracks by sensing the back-scattered waves reflected from the defect. A thin-film antenna embedded in the material will harvest energy beamed from outside the engine to power sensor activation and radio frequency (RF) communication.

"Our concept is analogous to human skin. When damage occurs, a message is transmitted to the brain and the body reacts to it. This smart skin, applied to a turbine component, will signal information about its damage," Hudak said.

SwRI researchers are taking a multidisciplinary approach to developing the system and will integrate Institute capabilities in materials science, surface engineering, RF communication and magnetostrictive sensor technology, of which the Institute is a pioneer. SwRI is also working with turbine engine manufacturers to ensure technology transfer.

"The first phase of the project will be devoted to developing new sensing materials that are very thin, a few microns or less, and then demonstrating that we can produce elastic waves with these films. At the same time, another group of Institute engineers will be developing the antenna and RF communications," he said.

Temperatures in turbine engines can run from 600 degrees Fahrenheit in the front of the engine to 1,400 degrees Fahrenheit or more in the back, the "hot section" of the engine. These extreme temperatures coupled with the high stress conditions during turbine operation demand materials that can withstand a harsh environment.

"This is a challenging program, but if we can get this system to work in a turbine engine environment, we can get it to work in many other environments. These sensor systems could be applied to airframes, helicopter, ships - they may revolutionize how we monitor critical components," Hudak added.

Phase I began in November 2003 and is expected to run until November 2005. If Phase I is successful, SwRI could receive up to an additional $2.6 million to further develop this promising technology.

For more information, contact Deborah Deffenbaugh, Communications, (210) 522-2046, PO Drawer 28510, San Antonio, TX 78228-0510.

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