Low-velocity impact localization in a stiffened composite panel using a normalized cross-correlation method

This paper presents an experimental study on the low-velocity impact localization of complex composite structures. An impact localization algorithm, which localizes an impact source by comparing the normalized cross-correlation between the reference database and the obtained impact signals, was proposed. The proposed method was applied to a stiffened composite panel that consists of a main spar and stringers. Impact tests were conducted on the composite panel in which four multiplexed fiber Bragg grating (FBG) sensors were attached on the bottom surface. The verification results indicated that 20 verification points were successfully localized with the maximum error of 43.98 mm and average error of 14.23 mm using four FBG sensors. The effect of the number of sensors on the localization performance was also investigated. The comparison results revealed that the proposed method could localize an impact source using a reduced number of sensors. A single FBG sensor covered an area of 600 × 900 mm² of the stiffened composite panel with a maximum error of 64.76 mm and an average error of 17.86 mm using the proposed method. (paper)