Analyses by Global-Local Method of Ultrasonic Guided Waves Propagation in Pristine and Defective Plates for Accurate Quantitative SHM

Abstract

The efficient and accurate modeling of ultrasonic guided waves (UGWs) can be a very effective tool to optimize UGWs inspections and enable defect characterization when performing structural health monitoring (SHM). Among the several strategies, hybrid methods provide the capability of representing accurately the hosting structure and defect configurations, while leveraging the decreased computational costs of reducedorder and/or semi-analytical methods. In this work, the Global-Local method is used to simulate UGW propagation in composite plates with defects, to study the effect of the incident mode interaction with the scatterer and its features (size, location, local zone relation). To do so, the evolution of the method is presented to account for the inclusion of evanescent modes and to accommodate the forced solution framework. In the first improvement, the role of evanescent modes will be discussed with respect to accuracy and computational cost considerations, providing guidelines for effective UGW modeling in composite materials. In the second upgrade, the 2D time-space response to different spatial and temporal sources is observed and analyzed in terms of its spectral content, to differentiate pristine and defective conditions, in composite materials with increasing defect severity. These improvements in the numerical framework of the Global-Local approach are significant to enable quantitative SHM and prognostics by accurate and efficient predictions of UGW scattered responses, and to advance defect characterization by UGWs by analyses of UGW data.