Researchers at Southwest Research Institute were awarded a $1.7 million contract from The Defense Advanced Research Projects Agency (DARPA) to develop a wireless sensor system for crack detection and monitoring in turbine-engine components.

Temperatures in turbine engines run from 600 to 1,400°F. These extreme temperatures, coupled with high-stress conditions during turbine operation, demand materials that withstand a harsh environment. Currently, it is unreliable to sense cracks indirectly through means such as monitoring the dynamic response of turbine shaft and blade-tip displacements. Direct monitoring is handicapped by the heat and stress produced by jet engines.

"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," says Stephen Hudak, an SwRI scientist in the mechanical and materials engineering division.

Ultrasonic waves will be periodically injected into components 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 the sensor. "These sensor systems could be applied to airframes, helicopters, ships, etc. They may revolutionize how we monitor critical components," adds Hudak.