Description: The pace and progress of new sensor technology development continues to lag far behind the broad ranging potential offered by guided wave NDE. In response to NASA solicitation H13.01 for Advanced NDE Techniques for Complex Built-up Structures, Advanced Systems and Technologies Inc., propose a collaborative program which seeks to combine an advanced sensor technology for rapid wide-area capture of ultrasound wave-field data with recent advances in NDE guided wave signal processing. This proposal describes how the Spatially Coherent Optical Vibrometer Array (SCOVA), combined with chirped ultrasound excitation and narrow tone-band decomposition provide deep data sets for application of new spatio-temporal and spatio-spectral analyses to address a broad range of NDE functions pertinent to NASA spaceflight structures. In form and function, SCOVA offers a sensor geared towards practical deployment of guided wave NDE. The ability of SCOVA to capture swept ultrasound data at hundreds of points simultaneously, offers a major advancement in the practical application of guided wave NDE targeting multiple defect modalities in current and future complex spaceflight structures.

Benefits: SCOVA facilitates multi-tier search and damage assessment for NDE and structural health monitoring of complex spaceflight structures employing composites, thin light-weight metals and hybrids. Guided wave techniques offer a viable means for composite NDE to identify foreign body impact leading to hidden damage in the form of delaminations, disbonds, crushed core, kissing bonds, matrix cracking or for incipient micro-crack accumulation due to fatigue or thermal damage. In addition to corrosion and fatigue cracking in metals, guided wave inspection is also being actively investigated to meet the urgent NDE demands arising from the increasing deployment of titanium diffusion bonds and bonded joints in metal composite hybrids employed in spaceflight vehicle construction. In form and function, SCOVA is geared towards rapid deployment of guided wave inspection to a broad array of structural NDE tasks.

The application of the proposed NDE system is anticipated to be of immediate benefit to all branches of military and commercial aerospace organizations concerned with aircraft maintenance and general fleet airworthiness. A broad range of application is anticipated by virtue of the sensors integration of advanced fiber optic component technology with very large scale integrated (VLSI) digital electronics which provides a robust instrument architecture suited to both flight-line and field deployment. In particular, the scope of application is further enhanced because the same SCOVA technology in conjunction with different modes of acoustic and ultrasonic excitation, offers an NDE instrument which is broadly applicable to detection of delamination, disbonds and hidden crushed core damage resulting from foreign body impacts and, potentially, bond line adhesion failure. However the potential areas of application extend beyond this to space, automotive, industrial and maritime fields where composite structures are similarly employed for a wide variety of applications due to their light weight and strength.