Impact localization for composite plate based on detrended fluctuation analysis and centroid localization algorithm using FBG sensors

Structure health monitoring of composite structures is essential for safety assurance and attracted more attention in recent years. In this paper, a low velocity impact (LVI) monitoring system based on detrended fluctuation analysis (DFA) and centroid localization algorithm is proposed. First, the distance from the LVI to neighboring FBG sensors can be estimated by analyzing the Hurst exponents calculated from response signal of LVI with different distance to monitoring FBG sensors by DFA. Then, the LVI location can be determined by region identification algorithm and centroid localization algorithm. To verify the performance of the proposed LVI monitoring system, a LVI localization system using optical fiber Bragg grating (FBG) sensor was constructed and validated on a CFRP plate with 240 mm*240 mm*3 mm experiment area. The experiment results showed that the average error of localization was 31.5 mm. The proposed localization method based on DFA and centroid localization algorithm demonstrates an effective means of LVI localization.