Wavelet signal processing for enhanced Lamb-wave defect detection in composite plates using optical fiber detection

1997 ◽  
Vol 36 (7) ◽  
pp. 1877 ◽  
Author(s):  
S. Gareth Pierce
Keyword(s):  
Signal Processing ◽  
Optical Fiber ◽  
Defect Detection ◽  
Lamb Wave ◽  
Composite Plates

Influence of Adhesive Layer on Actuation of Lamb Wave Signals

2012 ◽  
Vol 525-526 ◽  
pp. 617-620 ◽  
Author(s):  
Z. Sharif-Khodaei ◽  
Qu Liu ◽  
M.H. Aliabadi
Keyword(s):  
Lamb Wave ◽  
Adhesive Layer ◽  
Composite Plates ◽  
Wave Generation ◽  
Actuation Frequency ◽  
Adhesive Thickness

In this work, Lamb wave generation and propagation have been modelled in composite plates. Actuation and acquisition of signals when the PZT transducers are tied to the structure or bonded with an adhesive layer are investigated. The effect of adhesive thickness and actuation frequency of Lamb wave have been examined.

scholarly journals Development of Laboratory-scale Lamb Wave-based Health Monitoring System for Laminated Composites

2021 ◽  
Vol 53 (4) ◽  
pp. 210407
Author(s):  
Leonardo Gunawan ◽  
Muhammad Hamzah Farrasamulya ◽  
Andi Kuswoyo ◽  
Tatacipta Dirgantara
Keyword(s):  
Damage Detection ◽  
Health Monitoring ◽  
Lamb Wave ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laboratory Scale ◽  
Optimum Number ◽  
Detection Scheme ◽  
Damage Location ◽  
Location Detection

This paper presents the development process of a laboratory-scale Lamb wave-based structural health monitoring (SHM) system for laminated composite plates. Piezoelectric patches are used in pairs as actuator/sensor to evaluate the time of flight (TOF), i.e. the time difference between the transmitted/received signals of a damaged plate and those of a healthy plate. The damage detection scheme is enabled by means of evaluating the TOF from at least three actuator/receiver pairs. In this work, experiments were performed on two GFRP plates, one healthy and the other one with artificial delamination. Nine piezoelectric transducers were mounted on each plate and the detection of the delamination location was demonstrated, using 4 pairs and 20 pairs of actuators/sensors. The combinations of fewer and more actuators/sensor pairs both provided a damage location that was in good agreement with the artificial damage location. The developed SHM system using simple and affordable equipment is suitable for supporting fundamental studies on damage detection, such as the development of an algorithm for location detection using the optimum number of actuator/sensor pairs.

Determination of Vibration Source Locations in Laminated Composite Plates Using Lamb Wave Analysis

2010 ◽  
Vol 123-125 ◽  
pp. 899-902
Author(s):  
Chao Du ◽  
Qing Qing Ni ◽  
Toshiaki Natsuki
Keyword(s):  
Lamb Wave ◽  
Guided Waves ◽  
Lamb Waves ◽  
Laminated Composite ◽  
Composite Plates ◽  
Wave Dispersion ◽  
Laminated Plates ◽  
Vibration Source ◽  
Arrival Times ◽  
Wave Velocities

Signals propagate on plate-like structures as ultrasonic guided waves, and analysis of Lamb waves has been widely used for on-line monitoring. In this study, the wave velocities of symmetric and anti-symmetric modes in various directions of propagation were investigated. Since the wave velocities of these two modes are different, it is possible to compute the difference in their arrival times when these waves propagated the distance from the vibration source to sensor. This paper presents an evaluation formulation of wave velocity and describes a generalized algorithm for locating a vibration source on a thin, laminated plate. With the different velocities of two modes based on Lamb wave dispersion, the method uses two sensors to locate the source on a semi-infinite interval of a plate. The experimental procedure supporting this method employs pencil lead breaks to simulate vibration sources on quasi-isotropic and unidirectional laminated plates. The transient signals generated in this way are transformed using a wavelet transform. The vibration source locations are then detected by utilizing the distinct wave velocities and arrival times of the symmetric and anti-symmetric wave modes. The method is an effective technique for identifying impact locations on plate-like structures.

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