scholarly journals Delamination Localization in Sandwich Skin Using Lamb Waves by Finite Element Method

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Salah Nissabouri ◽  
Mhammed El allami ◽  
El Hassan Boutyour ◽  
Ahmed Errkik
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Lamb Waves ◽  
Arrival Times ◽  
Localization Method ◽  
Waves Propagation ◽  
Signal Changes ◽  
2D Fft ◽  
Mode A ◽  
Element Method

In this work we model by finite element method (FEM) the Lamb waves’ propagation and their interactions with symmetric and asymmetric delamination in sandwich skin. The simulations were carried out using ABAQUS CAE by exciting the fundamental A0 Lamb mode in the frequency 300 kHz. The delamination was then estimated by analysing the signal picked up at two sensors using two technics: Two-Dimensional Fast Fourier Transform (2D-FFT) to identify the propagating and converted modes, and wavelet transform (WT) to measure the arrival times. The results showed that the mode A0 is sensible to symmetric and asymmetric delamination. Besides, based on signal changes with the delamination edges, a localization method is proposed to estimate the position and the length of the delamination. In the last section an experimental FEM verification is provided to validate the proposed method.

Modelling of Lamb Waves Propagation in Orthotropic Plate

2020 ◽  
pp. 315-340
Author(s):  
Salah Nissabouri ◽  
Mhammed El Allami ◽  
El Hassan Boutyour
Keyword(s):  
Finite Element Method ◽  
Orthotropic Plate ◽  
Lamb Waves ◽  
Two Dimensional ◽  
Arrival Times ◽  
Localization Method ◽  
Waves Propagation ◽  
Signal Changes ◽  
2D Fft ◽  
Lamb Mode

In this chapter, we model by Finite Element Method (FEM) the Lamb waves' propagation and their interactions with symmetric and asymmetric delamination in sandwich skin. Firstly, a theoretical model is established to obtain the equation of lamb modes propagation. Secondly, dispersion curves are plotted using Matlab program for the laminate [0]4. The simulations were then carried out using ABAQUS CAE by exciting the fundamental A0 Lamb mode in the frequency 300 kHz. The delamination was then estimated by analyzing the signal picked up at two sensors using two techniques: Two Dimensional Fast Fourier Transform (2D-FFT) to identify the propagating and converted modes, and Wavelet Transform (WT) to measure the arrival times. The results showed that the mode A0 is sensible to symmetric and asymmetric delamination. Besides, based on signal changes with the delamination edges, a localization method is proposed to estimate the position and the length of the delamination. In the last section, an experimental FEM verification is provided to validate the proposed method.

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