Sensors Detect Aircraft Damage As It Occurs

For the first time, researchers have successfully developed and tested networked acoustic emission sensors that can detect airframe damage on conceptual composite UH-60 Black Hawk rotorcraft, according to an announcement from the U.S. Army Research Laboratory (ARL). The discovery could lead to onboard features that immediately alert the flight crew to the state of structural damage, such as matrix cracking and delamination as they occur, giving the crew more time to take corrective actions before catastrophic failure.

ARL researchers have been studying several possible alternatives to rotorcraft airframe health monitoring. This effort, which began almost two years ago, makes a strong case for integrated real-time damage sensing methodologies on future airframe structures. The sensing method can be used to reliably detect and locate the initiation and growth of damage that may occur during service.

The team turned to acoustic emission tests because other methods such as ultrasonic and radiography require an external energy source in the form of a directed wave. The external energy interferes with other aircraft systems, and alternative methods are less effective than acoustic emission at detecting damage.

Acoustic emission sensing is a nondestructive technique for detection of damage in the very early stage and long before the structure experiences catastrophic failure. Unlike other methods, acoustic emission detects damage at the instant the damage is happening. It also is considered passive, meaning it does not require an external energy source to detect damage. It relies on the energy that is initiated within the structure.

The ARL teamed with Army Aviation and Missile Research, Development, and Engineering Center researchers on this project.