Session: Nonlinear Ultrasonic Techniques for NDE

Paper Number: 169372

169372 - Refining Nonlinear Guided Wave Signals With Metafilters for Enhanced Defect Detection 

Abstract: 

Ensuring the structural integrity of thin plates through structural health monitoring (SHM) requires the early detection of minute imperfections such as microcracks at incipient stages. Nonlinear Lamb waves, which are characterised by the generation of higher-order harmonics, present a highly sensitive method for identifying these subtle defects. However, effective signal analysis is challenged by extraneous nonlinear effects intrinsic to the system, which frequently mask genuine indicators of structural damage. To address this critical issue, advanced filtering techniques are essential for a reliable signal interpretation. This study introduces a novel metafilter comprising specifically engineered metallic rings to eliminate the unwanted harmonics induced by the system itself. The proposed metafilter utilises high-frequency stopbands to effectively attenuate undesired second harmonics without significantly compromising the wave-propagation distance. A comprehensive investigation into the frequency responses and mode shapes was conducted to reveal the wave dynamics when interacting with the metafilter. The performance of the filter was validated through rigorous three-dimensional time-step numerical simulations that accurately replicated wave-filter interactions. Experimental verification is provided by tests involving thin aluminium plates fitted with 3D-printed metafilters constructed from steel and aluminium materials, confirming the practical efficacy of the proposed design. Ultimately, this study highlights the critical role of metafilters in enhancing the reliability of nonlinear Lamb wave-based diagnostics. It offers a robust and practical solution for early damage detection, thereby significantly advancing the application of SHM methodologies in real-world scenarios.

Presenting Author: Jaesun Lee Changwon National University

Presenting Author Biography: Prof. Lee, Jaesun is a professor in School of Mechanical Engineering and currently serves as the Research Vice Dean of Glocal Advanced Institute of Science and Technology, Changwon National University, Korea.

He obtained PhD from the Pusan National University, Korea in the year 2015. He worked at Korea Railroad Research Institute (KRRI), Korea for one and half year and he joined the school of mechanical engineering of Changwon National University (CWNU), South Korea as a tenure-track faculty.

His research includes ultrasonic NDE and Structural Health Monitoring, long range guided wave inspection technology, theoretical wave scattering analysis, tomographic defect imaging, structural Analysis and nonlinear ultrasonics material characterization. He won Global Ph.D Fellopwship from Korean government in 2011 for 3 years. Also, he won over 20 of best paper and presentation awards from Korean Society for Precision Engineering, the Korean Society of Mechanical Engineers, the Korean Society for Nondestructive Testing and the Korean Society for Railway.

He is currently leading the NDE research group of CWNU and with several national funding projects including National Regional Leading Research Center.

Authors:

Mohammed Aslam Changwon National University
Boris I Changwon National University
Jaesun Lee Changwon National University