Sponsors / Collaborators: National Science Foundation, University of Bristol

Ultrasonic inspection has been shown to be an effective technique for detecting damage in plate-like structures. Using this approach, piezoelectric sensors can be arranged on a structure and used to excite waves that travel throughout the structure and are received by other sensors. When the structure suffers damage, its wave propagation characteristics change, allowing the damage to be detected. Our emphasis has been to extend the ultrasonic guided wave paradigm to monitoring more complex structures. We have developed theoretically and demonstrated experimentally an optimal technique for damage detection with sparse array systems. Bolted joints, structures with many stiffeners, holes, and other geometrical features, and composite materials are all examples of structures that have been successfully tested using these methodologies.

Moving forward, damage localization techniques will be investigated for complex structures. Localization with sparse arrays in the presence of many benign structural features is an even more challenging problem, requiring the use of statistical models of the wave propagation process. Sensor fusion—that is, taking the data from multiple sensors in an array and combining that data intelligently—will also be considered in order to improve the accuracy of the results.