Ultrasonic reflection and guided waves in fluid-coupled composite laminates

1990 ◽  
Vol 9 (2-3) ◽  
pp. 51-69 ◽  
Author(s):  
D. E. Chimenti ◽  
Adnan H. Nayfeh
Keyword(s):  
Composite Laminates ◽  
Guided Waves

Fiber bragg grating based detection of part-thickness cracks in bent composite laminates using feature-guided waves

2019 ◽  
Vol 28 (8) ◽  
pp. 085026 ◽  
Author(s):  
Pabitro Ray ◽  
Xudong Yu ◽  
Zheng Fan ◽  
Balaji Srinivasan ◽  
Prabhu Rajagopal
Keyword(s):  
Fiber Bragg Grating ◽  
Composite Laminates ◽  
Guided Waves ◽  
Bragg Grating ◽  
Part Thickness

Guided wave-based detection of delamination and matrix cracking in composite laminates

2010 ◽  
Vol 225 (1) ◽  
pp. 123-131 ◽  
Author(s):  
T Wandowski ◽  
P Malinowski ◽  
P Kudela ◽  
W Ostachowicz
Keyword(s):  
Composite Laminates ◽  
Guided Waves ◽  
Guided Wave ◽  
Matrix Cracking ◽  
Detection Methods ◽  
Localization Algorithm ◽  
Reflected Waves ◽  
Signal Processing Algorithms ◽  
Pulse Echo ◽  
Pulse Echo Method

The aim of this article was a numerical and experimental study of the active damage detection methods based on piezoelectric elements attached to a composite laminate. In considered case, guided waves were excited and received in a structure using pulse-echo method. It means that after exciting a structure with a pulse, an array of sensors located on a structure was used to ‘listen' for reflected waves coming from discontinuities. The main part of structural health monitoring system is signal-processing algorithms, which allow to detect and localize damage. Algorithm applied in this research results in special maps that indicate damage location. In this article, a damage localization algorithm was described and experimentally tested. The proposed method was successfully tested on a carbon—epoxy part of a helicopter.

scholarly journals An integrated numerical model for investigating guided waves in impact-damaged composite laminates

2017 ◽  
Vol 176 ◽  
pp. 945-960 ◽  
Author(s):  
B. Zhang ◽  
X.C. Sun ◽  
M.J. Eaton ◽  
R. Marks ◽  
A. Clarke ◽  
...  
Keyword(s):  
Numerical Model ◽  
Composite Laminates ◽  
Guided Waves

scholarly journals Assessment of the Length and Depth of Delamination-Type Defects Using Ultrasonic Guided Waves

2020 ◽  
Vol 10 (15) ◽  
pp. 5236 ◽  
Author(s):  
Vykintas Samaitis ◽  
Liudas Mažeika ◽  
Regina Rekuvienė
Keyword(s):  
Composite Laminates ◽  
Guided Waves ◽  
Structural Integrity ◽  
Ultrasonic Method ◽  
Green Energy ◽  
Guided Wave ◽  
Engineering Structures ◽  
Length Estimation ◽  
The Difference ◽  
2D And 3D

Fiber-reinforced composite laminates are being increasingly used in various engineering components in the sectors of aerospace and green energy. Due to impacts throughout the service life of the structure, matrix breakage and delaminations significantly altering the structural integrity of the laminate can occur. Hence, robust guided wave structural health monitoring systems are required to ensure continuous safety of engineering structures. In this paper, the ultrasonic method based on the analysis of A0 mode reflecting within the defected area has been proposed to extract the length and the depth of the delamination-type defect. The technique proposed in this study extracts the depth of the damage by analyzing the magnitude variations of direct A0 mode which are caused by the difference of wave velocities in the upper and lower sub-laminates. This results in an altering and frequency-dependent forward-scattered amplitude of direct A0 mode. Furthermore, the proposed approach uses previously obtained information about the depth of the defect, which allows for the determination of the phase velocities of A0 and S0 modes in the upper and lower sub-laminates. As a result, the accuracy of the damage length estimation is increased. The performance of the proposed method was proven with 2D and 3D numerical simulations and experiments on samples with artificial defects. The method validation results showed that the proposed method with some limitations is capable of extracting the length of delamination with an approximate error below 6%.

Elastic Guided Waves in Bistable Composite Structures – Experimental and Numerical Investigation

2021 ◽  
Vol 01 ◽  
Author(s):  
D.M. Saad ◽  
S. Mustapha ◽  
A. Firouzian ◽  
A. Abdul Aziz
Keyword(s):  
Wave Propagation ◽  
Health Monitoring ◽  
Composite Laminates ◽  
Composite Structures ◽  
Guided Waves ◽  
Flaw Detection ◽  
Composite Plates ◽  
Stable Configuration ◽  
Propagation Behavior ◽  
Wave Modes

Background: Bistable composite laminates are emerging as smart structures in automotive and aerospace applications. However, the behavior of the wave propagation within such laminates has not been investigated, which hinders their implementation in structural health monitoring (SHM) and non-destructive evaluation (NDE). Objective: As a result, this manuscript examines the propagation behavior of guided waves in bistable composite structures. By understanding the effect of pre-stressing in bistable composite laminates on the characteristics of propagating waves, such as velocity and amplitude, a more knowledgeable decision about their applications in flaw detection and assessment can be made. Methods: The fundamental symmetric (S0) and anti-symmetric (A0) Lamb wave modes were investigated during propagation in two bistable composite laminates, [0/90]T and [02/902]T, and were assessed experimentally and numerically using ABAQUS. For the tested frequencies, which ranged from 60 kHz to 250 kHz, the behavior of the propagating wave was evaluated for both stable configurations and across two different actuators that were lined up with the fiber directions. Signal processing techniques were thus extensively used to enhance the measured signals and identify both the group velocities and the amplitudes’ trend of the S0 and A0 wave modes. Results: Our results showed that there is a minimal variation (typically below 1%) in the amplitude and velocity of the A0 and S0 modes when the composite plates switch between the first stable configuration and the second stable configuration in both composite plates. These results were numerically validated by replicating the bi-stability of the composites. The numerical data were in relatively close agreement (10% average error) with the experimental values and trends. Furthermore, the bistable effect was examined in detail relative to a reference numerical flat (monostable) plate. Although the bistable effect induced a notable amount of internal residual stress, this did not significantly impact the propagating wave modes, with a maximum difference of about 2% when comparing wave velocities. Conclusions: The effect on the wave propagation behavior along different directions of both stable configurations was shown to be minimal. These results, which were validated numerically, clear the ambiguity on the usage of these laminates in experimental health monitoring.

Modelling Anisotropy Influence on Guided Wave Scattering at Composite Delaminations

2021 ◽  
Author(s):  
Flora Hervin ◽  
Paul Fromme
Keyword(s):  
Composite Laminates ◽  
Guided Waves ◽  
Impact Damage ◽  
Scattered Wave ◽  
Unidirectional Composite ◽  
Guided Wave ◽  
Parameter Study ◽  
Laser Vibrometer ◽  
Composite Panels ◽  
Isotropic Composite

Abstract Carbon fibre reinforced composite laminates are widely used in aerospace structures but are prone to barely visible impact damage (BVID). Depending on impact severity, delaminations can form below the surface of the laminate, reducing the load bearing capacity. Efficient structural health monitoring (SHM) of composite panels can be achieved using guided waves propagating along the structure. Propagation and scattering of the A0 Lamb wave mode in a quasi-isotropic composite laminate was modelled using full three-dimensional (3D) Finite Element (FE) simulations. Individual ply layers were modelled using homogeneous unidirectional composite material properties to accurately capture the anisotropy effects. FE predictions for scattering and energy trapping at delaminations were compared to experimental measurements. Noncontact, full-wavefield guided wave measurements were obtained using a laser vibrometer. Good agreement was found between experiments and FE predictions. The effect of delamination shape and depth was investigated through a numerical parameter study. The angular dependency of the amplitude of the scattered wave was calculated. The influence of ply layer anisotropy on wave propagation in an undamaged laminate was investigated numerically. The sensitivity of guided waves for the detection of delaminations due to barely visible impact damage (BVID) in composite panels has been verified.

Analysis of Acoustic Pulses Reflected From Fiber-Reinforced Composite Laminates

1992 ◽  
Vol 59 (2S) ◽  
pp. S136-S144 ◽  
Author(s):  
A. K. Mal ◽  
C.-C. Yin ◽  
Y. Bar-Cohen
Keyword(s):  
Composite Laminates ◽  
Guided Waves ◽  
Wave Attenuation ◽  
Spectral Characteristics ◽  
Ray Theory ◽  
Frequency Range ◽  
Theoretical Simulation ◽  
Reinforced Composite ◽  
Time Histories ◽  
Irregular Behavior

The time histories and spectral characteristics of acoustic pulses reflected from fiberreinforced composite laminates immersed in water are recorded in the laboratory and analyzed through a generalized ray theory and an exact theory. Calculated results for an unidirectional laminate and two angle-ply laminates are compared with measured data. It is shown that for a unidirectional laminate a finite number of mode-converted waves contribute to the overall signal reflected from a thick specimen resulting in certain irregular behavior of the reflected pulses. A phenomenological model of wave attenuation is introduced in the theoretical simulation and the damping parameters are shown to have a strong influence on the amplitude of the reflected pulses. The phase velocity of the guided waves in the laminates are shown to be nearly independent of water loading and material dissipation in a broad frequency range. Agreement between measured and calculated results is found to be excellent to very good in all cases.

Investigation on fundamental modes of guided waves propagating in symmetric and nonsymmetric composite laminates

2017 ◽  
Vol 231 (16) ◽  
pp. 2988-3000 ◽  
Author(s):  
L Maio ◽  
V Memmolo ◽  
F Ricci ◽  
ND Boffa ◽  
E Monaco
Keyword(s):  
Composite Laminates ◽  
Guided Waves ◽  
Mechanical Response ◽  
Isotropic Plate ◽  
Three Dimensional ◽  
Composite Plates ◽  
Guided Wave ◽  
Membrane Behavior ◽  
Isotropic Composite ◽  
Guided Wave Propagation

A quasi-isotropic composite laminate is constructed in an attempt to create a structure that behaves like an isotropic plate. Its membrane behavior is similar to that of the isotropic plate while the bending behavior is quite different from the latter. Moreover, the laminae may or may not be arranged symmetrically with respect to the midplane thereby resulting in a different mechanical response. In this work, guided wave propagation along multiple directions in symmetric and not symmetric quasi-isotropic plates is evaluated. Experimental and numerical results for the fundamental modes A0 and S0 are analyzed for the symmetric and nonsymmetric layups. An eight-node brick type element based on the three-dimensional theory is used in modeling to predict numerically the velocity of wave modes propagating in the graphite/epoxy composite plates. Agreement between experimental and numerical approaches is found and interesting dependencies between velocity of propagating modes and laminate stacking sequence are discussed. A final comparison with analytical dispersion curves obtained by the implementation of the global matrix method is discussed.

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