A parameter estimation based sparse representation approach for mode separation and dispersion compensation of Lamb waves in isotropic plate

Ultrasonic Lamb wave testing has been successfully applied in nondestructive testing. However, because of Lamb wave multimodal and dispersion characteristics, the received signals are often multimodal and overlapping, which makes them very complicated. This paper proposes a mode separation method by combining dispersion compensation with the independent component analysis of fourth-order cumulant. Taking two-mode overlapped signals as an example, the single-mode dispersion compensation is performed according to the measured distance difference between the two sets of signals. The two sets of signals are returned to the same distance. The fourth-order cumulant independent component analysis method is further used to process the Lamb wave signals of different superposition situations at the same distance. The corresponding mode signal contained in the two sets of signals is separated through the joint diagonalization of the whitened fourth-order cumulant matrix. The different modes are compensated and separated successively, achieving the multimodal signal separation. Experimental results in steel plates show that the presented method can accurately achieve mode separation for the multimodal overlapping Lamb waves. This is helpful for the signal processing of multimodal Lamb waves.

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Wideband dispersion removal and mode separation of Lamb waves based on two-component laser interferometer measurement *

Chinese Physics B ◽

10.1088/1674-1056/26/9/094301 ◽

2017 ◽

Vol 26 (9) ◽

pp. 094301 ◽

Cited By ~ 2

Author(s):

Yan-Feng Xu ◽

Wen-Xiang Hu

Keyword(s):

Laser Interferometer ◽

Lamb Waves ◽

Mode Separation ◽

Two Component

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A Method of Dispersion Compensation Based on Warped Frequency Transform

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.718-720.2062 ◽

2013 ◽

Vol 718-720 ◽

pp. 2062-2067 ◽

Cited By ~ 2

Author(s):

Shang Chen Fu ◽

Zhen Jian Lv ◽

Ding Ma ◽

Li Hua Shi

Keyword(s):

High Resolution ◽

Velocity Dispersion ◽

Lamb Waves ◽

Group Velocity Dispersion ◽

Dispersion Compensation ◽

Imaging Method ◽

Finite Element Software ◽

Damage Imaging ◽

Resolution Imaging ◽

Multi Mode

The use of Lamb waves for structural health monitoring (SHM) has complicated by its multi-mode character and dispersion effect, which impacts the damage positioning and high-resolution imaging. The group velocity dispersion curves of Lamb waves can be employed to warp the frequency axis, and then to establish warped frequency transform (WFT) to process Lamb waves. In this paper, received signals are directly compensated with warped frequency transform to suppress dispersion, and a new imaging method is proposed based on warped frequency transform. The propagation of Lamb waves in damaged aluminum plate is simulated by finite element software ABAQUS, results show that warped frequency transform can effectively compensate dispersive wave-packets, and high-resolution damage imaging can be obtained by the proposed method.

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Separation of Lamb waves by Bayesian parameter estimation

10.1063/1.1472803 ◽

2002 ◽

Author(s):

Stephen W. Kercel

Keyword(s):

Parameter Estimation ◽

Lamb Waves ◽

Bayesian Parameter Estimation

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Parametric Sparse Representation Method for Motion Parameter Estimation of Ground Moving Target

IEEE Sensors Journal ◽

10.1109/jsen.2016.2604046 ◽

2016 ◽

Vol 16 (21) ◽

pp. 7646-7652 ◽

Cited By ~ 6

Author(s):

Fu-Fei Gu ◽

Qun Zhang ◽

Yi-Chang Chen ◽

Wen-Jun Huo ◽

Jia-Cheng Ni

Keyword(s):

Parameter Estimation ◽

Sparse Representation ◽

Motion Parameter ◽

Moving Target ◽

Motion Parameter Estimation ◽

Representation Method

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Excitation series design and pulse compression synthesis for high-resolution Lamb wave inspection

Structural Health Monitoring ◽

10.1177/1475921718801996 ◽

2018 ◽

Vol 18 (5-6) ◽

pp. 1464-1478

Author(s):

Jiadong Hua ◽

Liang Zeng ◽

Jing Lin ◽

Liping Huang

Keyword(s):

Lamb Wave ◽

Pulse Compression ◽

Lamb Waves ◽

Dispersion Compensation ◽

Synthesis Method ◽

Side Lobe ◽

Main Lobe ◽

Window Functions ◽

Windowing Technique ◽

Lobe Width

Lamb wave pulse compression is a promising technique for ultrasonic nondestructive evaluation and structural health monitoring, in which the excitation waveform is designed to exhibit attractive auto-correlation characteristics including short main-lobe width and small side-lobe amplitude. However, narrowing main-lobe will increase side-lobe amplitude, and vice versa. Conventional time windowing technique is a balance between main-lobe width and side-lobe amplitude. An improvement over time windowing is proposed using pulse compression synthesis method. In this method, a series of excitation waveforms are used to actuate Lamb waves, each response is processed by pulse compression, and all the compression signals are summed together. The excitation series are constructed as linear chirps weighted with different combinations of rectangular and Hanning window functions. The selection of the combination coefficients is optimized to ensure best signal summation. The effectiveness of the proposed method is demonstrated by an experiment, and the robustness to inaccuracy in dispersion compensation is also evaluated. Application of the proposed method for damage detection is demonstrated by a further experiment.

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