COMPOSITE CERAMIC ARMOR DEFECT ANALYSIS USING PHASED ARRAY ULTRASOUND

摘要

A series of 16-inch square by 2-inch thick, multi-layered ceramic composite armor specimens, some of which had intentional design defects inserted between the layers, were inspected using a 128 element, 10MHz immersion phased array ultrasound system. To overcome some of the issues associated with the acoustic wave propagation in layered media, two digital signal processing methods (Fast Fourier Transform (FFT) and Wiener filtering) were employed. While previous work has been presented on the significant improvement in defect detection associated with these methods, the authors present a detailed and quantitative statistical analysis of these results. This analysis suggests that these intentional defects were a) not detectable when the defect was in a particular configuration, b) readily detectable in all cases for alternate defect position configurations, and c) clearly identifiable in most cases for those configurations. However, even in the configuration where intentional defects were not detected (owing to inherent design issues in the armor structure), significant variation in interfacial quality was observed and quantified, and these results will also be presented.