9th International Workshop on Structural Health Monitoring: A Roadmap to Intelligent Structures, September 10-12 2013, Palo Alto, California, USA
Acoustic Emission (AE) is recognized for its potential as a Structural Health Monitoring (SHM) technique, offering several advantages, such as passive sensing and wide area monitoring, making it particularly attractive for aerospace applications. Realistic structures, like aircraft wings for example, consist of structural elements of complex geometry, manufactured with different materials. Individually these elements may influence the performance of the SHM technique in detecting and locating structural damage. In this research, the capabilities of the AE technique to identify and locate damage in complex structures were assessed. These assessments were performed without disclosure of the damage location to the AE equipment operator. Four piezoelectric AE sensors were mounted on spars of the aircraft wing representative structure prior to conducting a series of constant amplitude loading fatigue tests. One of the spars contained a fatigue crack seeded at a location unknown to the damage monitoring analyst. The sensors monitored AE generated from the spars and event location estimates were obtained using time of flight analysis with a wave velocity value determined experimentally. The AE monitoring successful detected and located the hidden fatigue crack; this was independently verified by three nondestructive testing (NDT) methods.
Structural Health Monitoring 2013: A Roadmap to Intelligent Structures - Proceedings of the 9th International Workshop on Structural Health Monitoring1: 65–72.