Damage localization method for plate-like composite structure based on valid path optimization and search point matching

Abstract

In order to improve the damage localization accuracy and efficiency of composite structures, an improved energy positioning method combining valid path optimization and search point matching is proposed in this paper. Firstly, the damage index (DI) can be calculated according to the healthy and damaged signals, and the valid sensing paths are then obtained by combining the DI threshold set based on the healthy signal. Then, the ineffective search points are filtered out by comparing the time-of-flight (TOF) of search points with that of the damage. Finally, the accumulated energy for each effective search point can be calculated based on its TOF and the scattered signals on valid sensing paths. The geometric center of the region with the greatest energy concentration is considered as the damage position. The performance of the proposed method was verified by constructing experimental system. Experimental result shows that for 450 mm × 450 mm × 2.4 mm and 800 mm × 800 mm × 2.4 mm composite laminates, the average absolute positioning errors obtained by the proposed method are 2.69 mm and 5.00 mm respectively, and the maximum positioning errors are 8.85 mm and 11.66 mm respectively. This study can provide a new idea for damage detection in composite structures.