A Reference-Free Guided Wave Based Damage Localization Approach for Highly Dispersive Structures

Abstract

The detection and localization of in situ damage in complex sandwich material such as X-COR sandwich composites using guided wave based structural health monitoring techniques is difficult due to the highly dispersive media and complex geometry, which complicates the interpretation of the reflected wave modes induced by damage. In this paper, a novel reference-free damage localization framework is developed, whereby converted wave modes are studied using their time-space representations constructed from sensor arrays signals. The source of each wave mode is subsequently localized using linear regression techniques. The X-COR sandwich structure utilized in this research was manufactured to include seeded facesheet delaminations. Macro-fiber composite sensors were bonded to the panel surface and used to validate the developed framework. Excellent agreement is shown between the predicted and actual locations of delamination and actuator. The results indicate that mode conversion is an effective damage indicator, and the proposed time-space based damage localization framework is a promising structural health monitoring tool for highly dispersive media.