scholarly journals Scattering characteristics of Lamb waves from debondings at structural features in composite laminates

2012 ◽  
Vol 132 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Ching-Tai Ng ◽  
Martin Veidt
Keyword(s):  
Composite Laminates ◽  
Lamb Waves ◽  
Structural Features

Damage Identification by Embedded Piezoceramic Sensors in the Composite Plate

2006 ◽  
Vol 326-328 ◽  
pp. 1697-1700
Author(s):  
Heoung Jae Chun ◽  
Choong Hee Yi ◽  
Joon Hyung Byun
Keyword(s):  
Monitoring System ◽  
Health Monitoring ◽  
Composite Laminates ◽  
Damage Identification ◽  
Lamb Waves ◽  
Structural Systems ◽  
Detection Accuracy ◽  
Health Monitoring System ◽  
Localized Defects ◽  
The Many

The embedded structural health monitoring system is envisioned to be an important factor of future structural systems. One of the many attractions of in situ health monitoring system is its capability to inspect the structural systems in less intrusive way over many other visual inspections which require disassembly of built up structures when some indications have appeared that damages have occurred in the structural systems The vacuum assisted resin transfer molding (VARTM) process is used to fabricate woven-glass/phenol composite specimens which have the PZT sensor array embedded in them. The embedded piezoceramic (PZT) sensors are used as both transmitters and receivers. A damage identification approach is developed for a woven-glass/phenol composite laminates with known localized defects. Propagation of the Lamb waves in laminates and their interactions with the defects are examined. Lamb waves are generated by the high power ultrasonic analyzer. A real time active diagnosis system is therefore established. The results obtained show that satisfactory detection accuracy could be achieved by proposed method.

Prediction and Measurement of Lamb Wave from Debondings at Structural Features in Composite Laminates

2013 ◽  
Vol 558 ◽  
pp. 139-148 ◽  
Author(s):  
Ching Tai Ng ◽  
Martin Veidt
Keyword(s):  
Lamb Wave ◽  
Composite Laminates ◽  
Wave Scattering ◽  
Three Dimensional ◽  
Scattered Wave ◽  
Structural Features ◽  
Complex Structures ◽  
Detection Techniques ◽  
Fe Simulations ◽  
Good Agreement

The interaction of the fundamental anti-symmetric Lamb wave (A0) with debondings at structural features is investigated using experimental data and finite element (FE) simulations. In this study explicit three-dimensional (3D) FE simulations are employed, which allows the study of the scattered wave along different propagation directions. Good agreement between the FE predictions and the measurements are obtained that demonstrates that the 3D FE scattering model is able to accurately predict the Lamb wave scattering characteristics at debondings. The study show that the characteristics of Lamb wave reflected from the debondings at the structure feature is much more complicated than that from defects in flat composite laminates. Parameter studies show that the backward and forward scattering coefficient of Lamb wave is a function of debonding size to wavelength ratio and debonding location. This shows the potential of employing Lamb wave to identify the size and monitor the growth of the debondings. The findings of the study provide improved physical insights into the scattering phenomena, which are important to further advance damage detection techniques for complex structures made by composite laminates.

Lamb Wave Propagation in Anisotropic Laminates

1990 ◽  
Vol 57 (4) ◽  
pp. 923-929 ◽  
Author(s):  
G. R. Liu ◽  
J. Tani ◽  
K. Watanabe ◽  
T. Ohyoshi
Keyword(s):  
Wave Propagation ◽  
Energy Distribution ◽  
Hybrid Composite ◽  
Lamb Wave ◽  
Composite Laminates ◽  
Strain Energy ◽  
Lamb Waves ◽  
Energy Distributions ◽  
Phase Velocities ◽  
Lamb Wave Propagation

The wave propagation in arbitrary anisotropic laminates is investigated on the basis of an exact theory. The dispersion relations of Lamb waves are determined for graphite/epoxy symmetric angle-ply laminates and hybrid composite ones which consist of carbon/epoxy and glass/epoxy layers. The dispersion and anisotropy of phase velocities for fundamental modes are discussed in detail. The energy distributions in the thickness direction of laminates are calculated for each kind of Lamb wave. A hybrid composite laminate is found to have better capability in absorbing impact energy by analyzing the strain energy distribution during the wave propagation. The results of the strain energy distribution are useful in determining the arrangement and the fiber orientation of the layers of hybrid composite laminates.

Lamb Wave-Based Damage Location Detection Method of Composite Plate

2011 ◽  
Vol 301-303 ◽  
pp. 1260-1266
Author(s):  
Li Shao Zhang ◽  
Huan Guo Chen ◽  
Jian Min Li ◽  
Li Tian
Keyword(s):  
Group Velocity ◽  
Lamb Wave ◽  
Composite Laminates ◽  
Composite Plate ◽  
Velocity Dispersion ◽  
Lamb Waves ◽  
Group Velocity Dispersion ◽  
Dispersion Curves ◽  
Damage Location ◽  
The Difference

To understand more about Lamb waves on composite laminates damage detection features, the Lamb wave group velocity dispersion curves are calculated and plotted by using dichotomy method in MATLAB. The signal parameters are chosen according to Group velocity dispersion curves. The dynamic response signals of the composite plate are obtained by finite element method. Damage location is calculated by the actual group velocity of Lamb wave and time of flight of the difference signal before and after damage.

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