Researchers from the US Army have developed a series of new networked acoustic emission sensors, which are capable of detecting airframe damage that may occur during service.
The new sensors have been tested on-board the UH-60 Black Hawk rotorcraft by research staff at the US Army Research Laboratory (ARL) and the US Army Aviation and Missile Research, Development and Engineering Center.
The ARL has been studying the feasibility of several possible alternative rotorcraft airframe health-monitoring solutions for almost two years.
ARL research aerospace engineer Dr Mulugeta Haile said: “Future Army airframe structures are required to be lighter, safer and ultra-reliable.
“To achieve these, the Army must adopt a combined strategy of implementing advanced structural design methods, improved structural materials and integrated damage sensing and risk prediction capabilities.”
The sensors are distributed in multiple zones in order to maximise coverage and increase the probability of damage detection.
The sensing network comprises several lightweight transducers, which are enclosed in 3D-printed, non-intrusive sensor mounts.
Flight crew can be immediately alerted when structural damage such as matrix cracking and delamination occurs in the aircraft by using the acoustic emission sensing technology.
The non-destructive monitoring solution is capable of detecting damage in the very early stages and long before the structure experiences catastrophic failure, the US Army stated.
Haile added: “The novelty of the current work is that we introduced several new concepts on wave acquisition control and signal processing to recover damage related information in networked acoustic emission sensors.
“The ‘eureka moment’ was when the sensing network consistently identified and located the initiation and progression of damage during a prolonged fatigue test that lasted over 200,000 cycles, a feat that has never been achieved before.”
Signal distortion control parameters, acquisition timing control and 3D-printed sensor capsules have also been developed to support damage detection in complex rotorcraft structures.