Impact of Changing Temperature on Lamb Wave Propagation for Damage Detection

2013 ◽  
Vol 588 ◽  
pp. 140-148 ◽  
Author(s):  
Rafal Radecki ◽  
Wieslaw Jerzy Staszewski ◽  
Tadeusz Uhl
Keyword(s):  
Wave Propagation ◽  
Damage Detection ◽  
Lamb Wave ◽  
Structural Damage ◽  
Clustering Algorithm ◽  
Lamb Waves ◽  
Ultrasonic Waves ◽  
Effect Of Temperature ◽  
Propagation Parameters ◽  
Lamb Wave Propagation

Lamb waves are the most widely used guided ultrasonic waves for structural damage detection. One of the major problems associate with Lamb wave propagation is the effect of temperature on wave propagation parameters. It is important that these parameters are more sensitive to damage than to varying temperature. The paper demonstrates how amplitude and arrival time of Lamb waves are affected by temperature. The analysis is performed for the experimental data gathered from Lamb wave propagation in a damaged aluminium plate. A simple clustering algorithm is used to distinguish between "undamaged" and "damaged" conditions in the presence of changing temperature.

Structural damage detection using combined finite-element and model Lamb wave propagation parameters

2008 ◽  
Vol 223 (3) ◽  
pp. 769-777 ◽  
Author(s):  
C Ratnam ◽  
B S Ben ◽  
B A Ben
Keyword(s):  
Finite Element ◽  
Wave Propagation ◽  
Lamb Wave ◽  
Structural Damage ◽  
Pulse Generator ◽  
Ultrasonic Pulse ◽  
Element Analysis ◽  
Propagation Parameters ◽  
Set Up ◽  
Lamb Wave Propagation

This article presents a combined finite-element and model Lamb wave propagation parameters method for structural health monitoring. Modal analysis allows identifying the mode conversions induced by the defects. A simulation combining a planar, lossless finite-element analysis with Lamb wave propagation parameter is proposed. This analysis is performed on two aluminium bars in both undamaged and damaged states, where the two damaged states are: (a) one having a circular hole and (b) the other having a cut partway through the bar, perpendicular to the long axis of the bar. The Lamb wave propagation parameters are calibrated by using the ultrasonic pulse generator test set-up. The natural frequencies for the theoretical, finite element and experimental results are compared, and close agreement is found between the frequencies obtained experimentally and computationally.

scholarly journals Lamb Wave Based Structural Damage Detection Using Stationarity Tests

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6823
Author(s):  
Phong B. Dao ◽  
Wieslaw J. Staszewski
Keyword(s):  
Damage Detection ◽  
Unit Root ◽  
Lamb Wave ◽  
Structural Damage ◽  
Lamb Waves ◽  
Structural Damage Detection ◽  
Kpss Test ◽  
Wave Data ◽  
Lamb Wave Propagation ◽  
Adf Test

Lamb waves have been widely used for structural damage detection. However, practical applications of this technique are still limited. One of the main reasons is due to the complexity of Lamb wave propagation modes. Therefore, instead of directly analysing and interpreting Lamb wave propagation modes for information about health conditions of the structure, this study has proposed another approach that is based on statistical analyses of the stationarity of Lamb waves. The method is validated by using Lamb wave data from intact and damaged aluminium plates exposed to temperature variations. Four popular unit root testing methods, including Augmented Dickey–Fuller (ADF) test, Kwiatkowski–Phillips–Schmidt–Shin (KPSS) test, Phillips–Perron (PP) test, and Leybourne–McCabe (LM) test, have been investigated and compared in order to understand and make statistical inference about the stationarity of Lamb wave data before and after hole damages are introduced to the aluminium plate. The separation between t-statistic features, obtained from the unit root tests on Lamb wave data, is used for damage detection. The results show that both ADF test and KPSS test can detect damage, while both PP and LM tests were not significant for identifying damage. Moreover, the ADF test was more stable with respect to temperature changes than the KPSS test. However, the KPSS test can detect damage better than the ADF test. Moreover, both KPSS and ADF tests can consistently detect damages in conditions where temperatures vary below 60 °C. However, their t-statistics fluctuate more (or less homogeneous) for temperatures higher than 65 °C. This suggests that both ADF and KPSS tests should be used together for Lamb wave based structural damage detection. The proposed stationarity-based approach is motivated by its simplicity and efficiency. Since the method is based on the concept of stationarity of a time series, it can find applications not only in Lamb wave based SHM but also in condition monitoring and fault diagnosis of industrial systems.

Damage Detectability Model of Pitch-Catch Configuration in Composite Plates

2017 ◽  
Vol 754 ◽  
pp. 387-390 ◽  
Author(s):  
Nan Yue ◽  
Zahra Sharif Khodaei ◽  
Ferri M.H. Aliabadi
Keyword(s):  
Wave Propagation ◽  
Damage Detection ◽  
Health Monitoring ◽  
Lamb Waves ◽  
Composite Plates ◽  
Detection Algorithm ◽  
Probability Of Detection ◽  
Operational Conditions ◽  
Proposed Model ◽  
Lamb Wave Propagation

Detectability of damage using Lamb waves depends on many factors such as size and severity of damage, attenuation of the wave and distance to the transducers. This paper presents a detectability model for pitch-catch sensors configuration for structural health monitoring (SHM) applications. The proposed model considers the physical properties of lamb wave propagation and is independent of damage detection algorithm, which provides a generic solution for probability of detection. The applicability of the model in different environmental and operational conditions is also discussed.

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.

Cauchy formalism for Lamb waves in functionally graded plates

2018 ◽  
Vol 25 (6) ◽  
pp. 1227-1232 ◽  
Author(s):  
Sergey V. Kuznetsov
Keyword(s):  
Wave Propagation ◽  
Functionally Graded Materials ◽  
Lamb Wave ◽  
Lamb Waves ◽  
Functionally Graded ◽  
Functionally Graded Plates ◽  
Graded Materials ◽  
Anisotropic Plates ◽  
Transverse Inhomogeneity ◽  
Lamb Wave Propagation

Propagation of harmonic Lamb waves in plates made of functionally graded materials with transverse inhomogeneity is analyzed by applying Cauchy six-dimensional formalism previously developed for the study of Lamb wave propagation in homogeneous or stratified anisotropic plates. For anisotropic plates with arbitrary transverse inhomogeneity a closed form implicit solution for the dispersion equation is derived and analyzed.

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