Multi FBG sensor-based impact localization with a hybrid correlation interpolation method

Abstract To locate the impact source of a composite material structure with a series of fiber Bragg grating (FBG) sensors, a hybrid correlation interpolation method is proposed, in this paper, based on a weighted correlation analysis and a unidirectional cubic spline interpolation. First, the signals collected by FBG sensors are preprocessed on the frequency domain to reduce noise interference. Second, the impact similarity map is built by using the weighted cross-correlation value to estimate the location of the impact roughly. Third, the similarity map is further subdivided by the unidirectional cubic spline interpolation to increase the impact localization. Fourth, the FBG sensor network is experimental analyzed to optimize the layout and the structure of the FBG sensor network. The validity of the multi FBG sensor-based impact localization method is verified on a carbon fiber composite plate with a size of 650 × 500 (mm). The experimental result shows that the mean absolute error is 9.74 mm for our suggested method and 15.51 mm for the bicubic polynomial interpolation (BPI) algorithm, which is reduced by 5.77 mm. The maximum errors are 36.40 mm for the BPI algorithm while are reduced to 21.55 mm for our suggested method. Furthermore, the effect of FBG sensor combination layout and number on impact location accuracy is analyzed and compared. It shows that the sensor network layout of rectangular structure using four FBG sensors is a better choice after the comprehensive consideration of economic benefits, localization accuracy, and error rate.