Aircraft Composite Component Inspection System

"We propose to develop a whole-field optical sensor that can detect and quantify defects such as disbonds and delaminations in composite materials of aircraft structures. This measurement problem calls for high-resolution, full-field measurement, becauselarge areas must be tested and the locations and sizes of defects are initially unknown. Interferometric techniques are well suited for this type of task, since they can detect deformation anomalies in the mm range within a scalable field of view. Suchanomalies can then be used to identify defects. Two particular variations of speckle interferometry are especially promising for this application: absolute speckle interferometry and sheared speckle interferometry. A unique wavefront sensing technique willbe used to eliminate time-dependent fluctuations that normally render interferometry unusable in field applications. Shearing interferometry conceptually cancels disturbances, but in turn yields the displacement in an indirect way. Depending on type andbehavior of defects under the mechanical or thermal load used for testing, both variations will have advantages and disadvantages. We will determine, experimentally and theoretically, the optimal way to detect material flaws quickly and reliably, byapplying the methods on actual test specimens and will design a system that can be used in a laboratory and field environment. The proposed technique will benefit the military and commercial aer