More than ten years of Research and Development focused on phased-array inspection of aerospace Polymer Matrix Composites (PMCs) is presented. This work includes basic research designed to understand the propagation of ultrasound through composite materials, as well as optimization of phased-array probes and inspection strategies for composite parts. Successful implementations of these strategies for fully automated on-line inspections are presented including a discussion of how challenges were overcome and the promise of new acquisition and analysis tools. Composite materials present unique challenges for ultrasonic inspection including complex shapes and a wide range of potential flaws and defects. For automated inspections, part-to-part variability and the need to inspect at production rates pose additional challenges. The methodologies presented are based upon laboratory experiments performed in conjunction with modeling and simulations, which are used to optimize inspection strategies. A significant challenge that should not be under estimated is creating industrial-quality test specimens with realistic defects of known size and location that can be independently verified. In projects with industry and the Air Force Research Laboratory (AFRL), work has focused specifically on using surface-adaptive techniques to inspect parts with complex shapes including small convex and concave radii that are typically found on stringers, blades and wing structures.
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