Inter-tile Gap Detection in Vehicle Add-on Ceramic Armor Using Capacitive Sensing

摘要

Land armor vehicles are often equipped with add-on armor which includes a ceramic layer. This layer can be made of tiles arranged in a mosaic pattern to resist multiple projectile impacts. Manufacturers have difficulties to assemble the ceramic tiles while maintaining a constant inter-tile gap. Large gaps between the tiles diminish the add-on armor effectiveness. X-ray radiography is regularly used as a quality control method to visualize possible tile cracking and shifting in the ceramic armor, but this method presents challenges with regards to its field applicability. Single-sided, non-contact capacitive imaging is seen as an alternative non-destructive evaluation technique, capable of detecting and quantifying inter-tile gaps based on the dielectric differences between the air and the ceramic tiles. The sensor consists of coplanar electrodes and is moved at a fixed distance from the test piece. Moreover, the capacitive sensing is capable of detecting the inter-tile spacing through a layer of composite material that covers the ceramic tile array. This study investigates some capacitive sensor parameters, as well as various inspection settings for optimized gap detection and sizing.