scholarly journals Damage Localization of Composites Based on Difference Signal and Lamb Wave Tomography

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 218 ◽  
Author(s):  
Chenhui Su ◽  
Mingshun Jiang ◽  
Jianying Liang ◽  
Aiqin Tian ◽  
Lin Sun ◽  
...  
Keyword(s):  
Lamb Wave ◽  
Lamb Waves ◽  
Simple Calculation ◽  
Maximum Error ◽  
Differential Signal ◽  
Damage Location ◽  
Composite Damage ◽  
Damage Imaging ◽  
Wave Tomography ◽  
The Difference

In order to deal with the problem of composite damage location, an imaging technique based on differential signal and Lamb wave tomography was proposed. Firstly, the feasibility of the technique put forward was verified by simulation. In this process, the composite model was regularly set down by the circular sensor array, with each sensor acting as an actuator in sequence to generate Lamb waves. Apart from that, other sensors were used to collect response signals. With regard to the damage factor, it was mainly determined by the difference between the damage signal and the non-damage signal. The probabilistic imaging algorithm was employed to carry out damage location imaging. Then, experiments were carried out so as to study the selected composite plate. Finally, the tentative outcomes have illustrated that the maximum error of damage imaging position was 7.07 mm. The relative error was 1.6%. In addition, the method has the characteristics of simple calculation and high imaging efficiency. Therefore, it has large technical potential and wide applications in the damage location and damage recognition for composite material.

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.

scholarly journals Damage Identification of Large Generator Stator Insulation Based on PZT Sensor Systems and Hybrid Features of Lamb Waves

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2745 ◽  
Author(s):  
Ruihua Li ◽  
Hao Li ◽  
Bo Hu
Keyword(s):  
Power Systems ◽  
Lamb Wave ◽  
Damage Identification ◽  
Lamb Waves ◽  
Fem Simulation ◽  
Correlation Coefficients ◽  
Hybrid Features ◽  
Material Inhomogeneity ◽  
Time Frequency ◽  
Damage Imaging

Large generators are the principal pieces of equipment in power systems, and their operation reliability critically depends on the stator insulation. Damages in stator insulation will gradually lead to the failure and breakdown of generator. Due to the advantages of Lamb waves in Structural health monitoring (SHM), in this study, a distributed piezoelectric (PZT) sensor system and hybrid features of the Lamb waves are introduced to identify stator insulation damage of large generator. A hierarchical probability damage-imaging (PDI) algorithm is proposed to tackle the material inhomogeneity and anisotropy of the stator insulation. The proposed method includes three steps: global detection using correlation coefficients, local detection using Time of flight (ToF) along with the amplitude of damage-scattered Lamb wave, and final images fusion. Wavelet Transform was used to extract the ToF of Lamb wave in terms of the time-frequency domain. Finite Element Modeling (FEM) simulation and experimental work were carried out to identify four typical stator insulation damages for validation, including inner void, inner delamination, puncture, and crack. Results show that the proposed method can precisely identify the location of stator insulation damage, and the reconstruction image can be used to identify the size of stator insulation damage.

A Bayesian fusion method for composite damage identification using Lamb wave

2020 ◽  
pp. 147592172094500
Author(s):  
Haode Huo ◽  
Jingjing He ◽  
Xuefei Guan
Keyword(s):  
Lamb Wave ◽  
Composite Plate ◽  
Damage Identification ◽  
Reconstruction Algorithm ◽  
Damage Location ◽  
Numerical Studies ◽  
Composite Damage ◽  
Bayesian Fusion ◽  
Novel Method ◽  
Reliability And Robustness

This study presents a novel method for composite damage identification using Lamb wave. A probabilistic integration of the elliptical loci method and the RAPID (reconstruction algorithm for probabilistic inspection of defects) in a Bayesian framework is proposed. The proposed method allows for the incorporation of multiple damage sensitive features in a rational manner to improve the reliability and robustness for a given array of sensors. Numerical studies are performed to verify the effectiveness of the proposed method and to compare its accuracy with existing methods. Experimental investigation using a realistic composite plate is made to further validate the proposed method. The influence of damage location and the number of participating sensors on the performance of the proposed method is discussed. Results indicate that the proposed method yields more accurate and reliable results comparing with existing methods.

Lamb-Wave Based Damage Detection in Anisotropic Composite Plates

2014 ◽  
Vol 627 ◽  
pp. 1-4 ◽  
Author(s):  
Z. Sharif-Khodaei ◽  
M.H. Aliabadi
Keyword(s):  
Damage Detection ◽  
Lamb Wave ◽  
Lamb Waves ◽  
Composite Plates ◽  
Detection Algorithm ◽  
Damage State ◽  
Anisotropic Composite ◽  
Cfrp Composite ◽  
The Difference ◽  
Imaging Algorithms

Damage detection in anisotropic composite plates based on Lamb wave technique has been investigated. A network of transducers is used to detect barely visible damage caused by impact. A CFRP composite plate has been impacted and tested to verify the proposed damage detection algorithms. The difference in the propagational properties of Lamb waves in the pristine state and the damage state is used through data fusion and imaging algorithms to detect, locate and characterise the damage. The influence of directionality of the velocity on the validity of the detection algorithm is examined and some results are presented.

scholarly journals Numerical Study of Concrete Mesostructure Effect on Lamb Wave Propagation

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2570 ◽  
Author(s):  
Beata Zima ◽  
Rafał Kędra
Keyword(s):  
Particle Size ◽  
Wave Propagation ◽  
Lamb Wave ◽  
Lamb Waves ◽  
Numerical Study ◽  
Diagnostic Methods ◽  
Material Parameters ◽  
The Difference ◽  
Dispersion Solution ◽  
Lamb Wave Propagation

The article presents the results of the numerical investigation of Lamb wave propagation in concrete plates while taking into account the complex concrete mesostructure. Several concrete models with randomly distributed aggregates were generated with the use of the Monte Carlo method. The influence of aggregate ratio and particle size on dispersion curves representing Lamb wave modes was analyzed. The results obtained for heterogeneous concrete models were compared with theoretical results for homogeneous concrete characterized by the averaged macroscopic material parameters. The analysis indicated that not only do the averaged material parameters influence the dispersion solution, but also the amount and size of aggregate particles. The study shows that Lamb waves propagate with different velocities in homogeneous and heterogeneous models and the difference increases with aggregate ratio and particle size, which is a particularly important observation for wave-based diagnostic methods devoted to concrete structures.

Detection Principle of Shape and Orientation of Corrosive Defects Using Lamb Waves

2009 ◽  
Vol 21 (5) ◽  
pp. 568-573 ◽  
Author(s):  
Chunguang Xu ◽  
◽  
Joseph L. Rose ◽  
Xiang Zhao ◽  
◽  
...  
Keyword(s):  
Lamb Wave ◽  
Lamb Waves ◽  
Two Dimensions ◽  
Simulation Experiments ◽  
Special Shape ◽  
Transducer Array ◽  
Wave Tomography ◽  
Detection Principle

The shape and orientation of corrosive defects are critical in the evaluation of the reliability and durability of plate-like structures. And Lamb wave is considered as an effective tool for inspections of this kind corrosive plates. In this paper, the shape and orientation of plane defects are detected and presented using a circular transducer array with Lamb wave tomography approach. Here, considering a special shape defect with two-dimensions elliptical contour in the plate, the various ratios for both defect shape and orientation, individually representing different classifications of defects, is identified and investigated using Lamb wave tomography approach. And the validity of this approach has been proved through simulation experiments.

Damage imaging for composite using Lamb wave based on minimum variance distortion-less response method

2019 ◽  
Vol 41 (15) ◽  
pp. 4179-4186
Author(s):  
Chenhui Su ◽  
Mingshun Jiang ◽  
Shanshan Lv ◽  
Lei Zhang ◽  
Faye Zhang ◽  
...  
Keyword(s):  
Composite Materials ◽  
Lamb Wave ◽  
Composite Laminates ◽  
Damage Identification ◽  
Imaging System ◽  
Impact Damage ◽  
Near Field ◽  
Maximum Error ◽  
Minimum Variance ◽  
Damage Imaging

It is highly probable for the structures of carbon fiber reinforced plastics (CFRP) to suffer from invisible impact damage, for which the identification of such damage is of great significance. For the purpose of damage localization, this paper proposes a minimum variance distortion-less response (MVDR) algorithm that employs linear array sensor. In addition, a near field signal model based on active Lamb wave is established and the propagation of Lamb wave is investigated in composite laminates through the method of simulation. Moreover, a damage imaging system is also set up for composites to verify the effectiveness of the MVDR algorithm. Besides, in the study, wavelet transform is used as well to extract narrowband signals and promote signal-to-noise. It is shown by the results that the proposed algorithm can accurately identify the location of damage through the method of imaging. It is concluded that the maximum error of damage identification is 1.2 cm and MVDR algorithm has great potential in the field, damage imaging of composite materials. As a result, it provides a novel idea for damage imaging of composite materials.

scholarly journals Lamb Wave-Based Damage Localization Feature Enhancement and Extraction Method for Stator Insulation of Large Generators Using VMD and Wavelet Transform

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4205
Author(s):  
Ruihua Li ◽  
Jing Luo ◽  
Bo Hu
Keyword(s):  
Wavelet Transform ◽  
Lamb Wave ◽  
Background Noise ◽  
Lamb Waves ◽  
Signal To Noise Ratio ◽  
Scattered Wave ◽  
Damage Location ◽  
Wave Detection ◽  
Mode Decomposition ◽  
Reconstructed Signal

Lamb waves are used to locate any damage in the stator insulation structure of large generators. However, it is difficult to extract the features of Lamb wave signals in a strong background noise environment, thus significantly reducing the accuracy with which the damage is located. This paper proposes a method based on variational mode decomposition (VMD) and wavelet transform to enhance and extract the location features of stator insulation damage signals of large motors. First, considering that the characteristics of VMD are sensitive to noise, the Lamb wave detection signal is decomposed, denoised, and reconstructed; the reconstructed signal is then wavelet-transformed to extract the time of flight (TOF) of the damage-scattered wave as the damage location feature; finally, the damage location is determined using the TOF features. The proposed method is experimentally tested and verified under various noise environments. The results show that the VMD and wavelet transform methods can significantly improve the signal-to-noise ratio of Lamb wave detection signals and the accuracy with which the damage is located under strong background noise. This study extends the applicability of Lamb wave-based non-destructive detection of stator insulation damage in complex environments.

Lamb Wave Tomography and Its Application in Pipe Erosion/Corrosion Monitoring

1996 ◽  
Vol 8 (1) ◽  
pp. 189-197
Author(s):  
J. Pei ◽  
M. I. Yousuf ◽  
F. L. Degertekin ◽  
B. V. Honein ◽  
B. T. Khuri-Yakub
Keyword(s):  
Lamb Wave ◽  
Corrosion Monitoring ◽  
Erosion Corrosion ◽  
Wave Tomography

Simulation Study of Damage Identification Method Based on Lamb Wave Scattering in Aluminium Plate

2012 ◽  
Vol 433-440 ◽  
pp. 2611-2618
Author(s):  
Zhen Hua Tian ◽  
Hong Yuan Li ◽  
Hong Xu
Keyword(s):  
Energy Distribution ◽  
Lamb Wave ◽  
Damage Identification ◽  
Optimization Method ◽  
Propagation Path ◽  
Transient Dynamic Analysis ◽  
Time Frequency ◽  
Damage Location ◽  
Identification Method ◽  
Short Time

The propagation of scattering Lamb wave in plate was simulated using transient dynamic analysis in ANSYS. In order to extract the characteristic information of received signal for damage identification, the short time Fourier transform based on time-frequency analysis was utilized, and then the energy distribution and envelop of received signal were obtained. Based on the displacement contour of simulation and energy distribution, the propagation of scattering wave in plate with a through hole was examined. Also, a mathematic relationship between damage location and scattering signal was developed, with the help of wave propagation path through actuator, damage and sensor. A nonlinear optimization method was applied on the mathematic relationship to obtain the damage location. The damage identification method using scattering Lamb wave was therefore established.

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