Compact Optical System for Detection of Cracks in Composite Materials

MDA solicits a practical instrument for defect detection and damage assessment in ceramic matrix composite (CMC) components employed in system critical applications. Specifically, the technology must be capable of detecting small cracks or delaminations in an efficient, reliable, and cost effective way, providing useful information to aid in evaluating reliability and/or remaining lifetime of the component. To address the problem of flaw detection in composites, MetroLaser is currently developing Multiple Beam Laser Doppler Vibrometry (MB-LDV) predicated on the observation that changes in the surface vibrational pattern of the test subject reveal underlying structural defects within the material bulk. Measurement and analysis of the surface velocity spectrum by MB-LDV, therefore, serves to reveal the presence of subsurface material irregularities associated typically with disbonds and delaminations. This instrument would substantially increase inspection rates and provide a framework for the practical implementation of a portable, field-ready instrument that addresses inherent limitations in current scanning LDV systems. Phase II will consist of the analysis, design, and construction of a prototype MB-LDV diagnostic instrument for non-destructive, non-contact inspection of composite ceramic components.