Finite element analysis of guided waves in fiber metal laminates with delaminations
Publication date
2023
Document type
Konferenzbeitrag
Author
Organisational unit
Conference
10th ECCOMAS Thematic Conference on Smart Structures and Materials (ECOMAS SMART 2023) ; Patras, Greece ; July 3–5, 2023
Publisher
University of Patras
Book title
SMART 2023
First page
95
Last page
106
Peer-reviewed
✅
Part of the university bibliography
✅
Language
English
Abstract
The present work deals with the numerical analysis of the propagation of guided ultrasonic waves (GUW) in fiber-metal laminates (FML) and the effects resulting from their interaction with interlaminar damage.For this purpose, a numerical simulation including delaminations at different positions between layers is performed.FML is a hybrid material consisting of stacked layers of metal (e.g.steel) and fiber-reinforced polymer (FRP) and has been increasingly used in aerospace and lightweight construction over the past decade.In the context of Structural Health Monitoring (SHM), this novel material is still insufficiently explored in the case of damage detection using GUW.In the context of our work, it is of interest to investigate the different phenomena occurring during the interaction of the wave with the delamination and to formulate precise statements about its influence on the wave propagation.To explore the phenomena, three different models were considered: a defect-free model without delamination and two models with symmetrically and off-center located delamination, respectively.The simulation in this work is limited to a two-dimensional model, where the delamination is geometrically generated by de-merging the interface between the layers.In this case it is zero-thickness delamination.Moreover, the excitation is mode-selective and the investigated frequencies are in the range of fundamentally symmetric and antisymmetric modes.Thus, it is possible to consider the influence of the two modes separately.For the evaluation of the results different aspects were analyzed.First, the comparison of B-scans-representation show effects such as reflection, transmission and mode conversion when the guided wave hits the corners of the delamination.Furthermore, a singular phenomenon known as "trapped mode" is clearly observed, where the mode-converted wave remains confined within the delamination area.Finally, the comparison of the displacement fields across the thickness before, in, and after delamination shows that the wave continues to propagate over the entire thickness instead of separating into two independent waves shapes.
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