Germany's Fraunhofer Institute has developed an oscillating piezoelectric actuator system to detect damaged aircraft parts for structural health monitoring.

The response of aircraft structures to vibrations from a network of actuators is detected by another set of piezoceramic sensors, enabling the damage to be located.

A team at the Fraunhofer Institute for Structural Durability and System Reliability in Darmstadt has already performed laboratory tests on a hull component and is now implementing the system with standardised piezo and electronic components.

"We investigated the oscillation behaviour of damaged struts and rivets in an aircraft body and compared it with that of intact parts," says project manager Dirk Mayer. "If a component is defective, it oscillates at a different frequency from one that is intact when stimulated by the piezoceramics."

The US University of Missouri-Columbia is also working on structural health monitoring using piezoceramic actuators. That team's system detects cracks in composite structures using a laser to measure the vibration generated by the actuators (Flight International, 20-26 February).

Source: Flight International