Multi-dimensional signal processing and mode tracking approach for guided wave based damage localization in X-COR sandwich composite

This paper presents a real-time signal processing and damage localization framework for ultrasonic guided wave based structural health monitoring of X-COR sandwich composites with a reference-free perspective. The high attenuation nature of X-COR composite significantly limits the ability to detect damage-induced reflected waveforms. Therefore, a novel multi-dimensional signal processing technique, coupled with a mode tracking approach for identifying trajectories and locating wave sources of all wave modes, including damage-induced converted modes, is proposed. The developed framework is experimentally validated using two internal damage scenarios: facesheet delamination and foam core separation. Results indicate that the framework offers not only high accuracy for locating internal damage positions, but also insights into guided wave propagation behaviors in highly complex composites such as the X-COR sandwich composite. (C) 2018 Elsevier Ltd. All rights reserved.