Acoustic Emission Techniques for In-Flight Structural Monitoring

Faced with high replacement costs for airframes, commercial and military users are attempting to keep their high-time aircraft in service. Assistance comes from the field of acoustic emission (AE), which provides a means of monitoring structural integrity in cases where fatigue damage may jeopardize basic airworthiness. Acoustic emission are the distinctive stress waves generated in solid materials during crack growth. These stress waves can be detected by sensitive transducers coupled to the material surface. Sensing of AE signatures provides the basis for a system which can continuously monitor structural integrity during flight and warn of impending failure.