Rapid and Conformable Field Repair and Nondestructive Evaluation of Rotor Blade Skins and Honeycomb in Blade Afterbody

This proposal describes the development of a novel NDI instrument for rapid and reliable detection of skin to core and skin to honeycomb disbonds in aerospace structures. The proposed field instrument adapts a newly developed fiber-arrayed laser Doppler vibrometer (FA-LDV) to perform true defect detection and imaging as compared to the slow image synthesis employed in conventional point-scanning LDV instruments. This methodology has recently been successfully applied for detection of disbonds and delaminations in metal and composite airframe structures. The proposed effort aims to further extend this technology and design to engineer, assemble and field-test a portable, compact instrument capable of the reliable detection of core-skin disbonds as required by the NAVY. The Phase I study is anticipated to yield an analysis of the instrument configuration, assortment of its critical components, and working envelop estimation. An existing MetroLaser multi-beam LDV instrument will be employed in the Phase I study, to accelerate the process of getting signatures from the specimens with representative defects. These data will be used to design the fiber-optics breadboard system for performing proof-of-concept tests. The Phase I effort will culminate with a preliminary prototype design of an instrument to be developed and field-tested during Phase II.