Session: 04-01: Emerging Techniques & Technology

Paper Number: 135288

135288 - Delamination Detection and Investigation at Far-Field in Glare Laminates Using Lamb
Waves 

Abstract: 

For aerospace applications, glass-reinforced (GLARE) fiber metal laminate (FML) offers an intriguing advantage over aluminum and composite materials due to its superior physical characteristics. GLARE is made up of alternating layers of thin aluminum and glass fiber-reinforced prepregs. In contrast to monolithic constructions, GLARE is susceptible to internal damage during the fabrication or in-service phases. Large structures are usually sought, making non-destructive testing and evaluation (NDT&E) of GLARE still difficult. In this work, we examined the use of guided Lamb mode(s) for GLARE inspection, specifically for delamination. This work investigates the effectiveness of fundamental anti-symmetric Lamb wave mode (A0) for the detection of delamination in glass fiber aluminum laminates for two distinct configurations, GLARE01 (Al/0°/Al/0°/Al/0°/Al/0°/Al) and GLARE02 (Al/0°/Al/90°Al/90°Al/0°/Al). The plates used in this study were 500 mm x 500 mm x 2.5 mm, with the thickness of each aluminum layer measuring 0.3 mm and each GFRP layer 0.25 mm. The delamination was situated between the layers of the laminates at multiple sites, and sizes in the multiple of the operating wavelengths of launching mode. A numerical 3D and 2D finite-element (FE) method was used to conduct the testing. Validation was achieved by comparing methodologies and experimental results obtained in previous studies, including the author’s work. Results show that A0 Lamb mode effectively detects delamination in Fiber Metal Laminates (FMLs). Additionally, geometrical details are obtained from energy trapping inside the delamination, and positional information is obtained from the analysis of reflected waves. However, scattering reveals a more complex nature of the wave mode angularly and found that most of the energy is concentrated along the center line irrespective of the losses in metal fiber interfaces, indeed, depending upon the mode to be launched. Wave enters the delamination region very differently from the entry point of the aluminum-glass fiber interface and detection is found to be strongly bounded with the sublayer thickness and dispersion. Multiple delamination sites at single and multiple interfaces are explored and are traced when they are present simultaneously. Selecting the plane strain conditions resolves a few delamination case problems. This work provides additional insight on dispersion into the propagation of Lamb waves in FMLs and important information regarding the detectability of delamination in FMLs. A comparison between Hanning distortion of ultrasonic waves in long wavelength limits and CARALL (carbon fiber aluminum laminates) yields shreds of evidence, maybe illustrating the possible utility of a specific Lamb mode for severally weak interfaces for certain FMLs. When a portion of the region is inaccessible, the study will result in a new era of on-site identification and quick scanning of aerospace structures.

Presenting Author: SAURABH GUPTA Michigan State University

Presenting Author Biography: Saurabh Gupta received the B.Tech. degree in mechanical engineering from Uttar Pradesh Technical University Lucknow in 2009, the M.Tech. in mechanical engineering from National Institute of Technology Srinagar in 2013, and the doctorate of philosophy (Ph.D.) in Ultrasonic guided Waves for composite structures from the Center of non-destructive evaluation department (CNDE), IIT Madras of mechanical engineering in 2019. During his doctorate, he assisted in some consultancy projects in his research group for Renault Nissan, and Walmart. He conducted various experiments on the characterization of high reactive battery samples and watermelon for structure health monitoring (SHM) using ultrasonic bulk waves. From early 2019 to Nov 2019, he worked as a post-doctoral researcher on a research project, LIGO R&D in CNDE laboratory IITM. He joined Vellore Institute of Technology in Nov 2019 as an assistant professor in the School of mechanical engineering. Since 2019 he has been actively working in the NDT/E research domain and guided various research students. At present he joined (November 1, 2023) Michigan State University, East Lansing, MI-USA, as a Postdoc in the field of NDT/E of Materials. His research has addressed the detection of weak interfaces due to delamination and cracks in composites, ultrasonic-guided wave propagation in complex composites/aerospace structures, and onsite monitoring of ice-affected regions.

Authors:

SAURABH GUPTA Michigan State University
Mahmood Haq Michigan State University
Oleksii Karpenko Michigan State University
Lalita Udpa Michigan State University