A Novel CCCS Rolling Scanning Defect Detection Method for Nonmetallic Curved Surface Components

The primary application of coplanar capacitance detection lay in inspecting surface and subsurface defects in flat plate components. However, when examining nonflat structures, challenges emerged due to lift-off effects and probe tilt, which could exert a more significant influence on capacitance measurements than the defects themselves. This article introduced a novel rolling scan inspection methodology employing a cylindrical coplanar capacitance sensor (CCCS). The viability of this rolling scan approach was substantiated, involving arc-shaped specimens with intentionally introduced defects of various curvatures, examined using both flat coplanar capacitance sensors (FCCSs) and the CCCS. Moreover, an in-depth analysis of the CCCS’s inspection consistency was conducted. To enhance comparability, normalized capacitance values (NCVs) and goodness-of-fit analyses were introduced as metrics, enabling the quantification of the congruence between detected outcomes and the actual capacitance values.