Damage Identification Algorithms for Composite Structures

Current survivability and engineering requirements for airframe platforms necessitate the automated application of specialty coatings to the composite inlet duct OML surface. The specialty coatings have tight specification tolerances for the final thickness. Current equipment does not allow for accurate measuring of the specialty coatings. Measurement techniques and equipment need to be developed and tested to verify the application process achieves engineering requirements. The non-contact method of coating thickness measurement is a technology that allows for thickness measurements of the multiple specialty coatings applied over composite parts. Northrop Grumman Corporation has developed a non destructive, non contact measurement system which is a Dielectric Waveguide Arch (DWA). The DWA emits electromagnetic radiation at a specific frequency and receives the return signal from the article under test. The return signal can then be processed to provide the electromagnetic performance of the material under test. With proper calibration, the electromagnetic performance can be processed and converted to a coating thickness.