Damage imaging method for composites laminates based on sparse reconstruction of single-mode Lamb wave

As plate-like structures are widely used in railway vehicle systems, structural health monitoring and nondestructive testing of those structures are important. The Lamb wave, as an ultrasonic guided wave propagating in plate-like structures, is an effective tool for fault diagnosis. The Capon method is widely used in Lamb wave based damage imaging due to its superior performance in suppressing background noise compared with the conventional delay-and-sum method. As the conventional Capon method is sensitive to modelling errors like the inaccuracy of the look-direction, diagonal loading is usually adopted to regularize the inverse of the covariance matrix. However, the degree of diagonal loading is related to the accuracy of the given look-direction and is hard to determine accurately. Aimed at improving the imaging quality of the conventional Capon method, an adaptive Capon method with adaptive diagonal loading is proposed. In the proposed method, the dispersion and the amplitude caused by wave diffusion are first compensated for each imaing point using the virtual time reversal technique. The correlations among the compensated waveforms after windowing are used to determine the degree of diagonal loading. In the process of regularizing the inverse of the covariance matrix, a large diagonal loading factor will be applied when the correlations among the compensated waveforms are large. As correlations are closely related to the signal phase, both the amplitude and the phase of scattering signals are utilized in the proposed method. The numerical and experimental validations on an aluminum plate are carried out to verify the effectiveness of the proposed method. The results show that compared with the conventional Capon method, the proposed method can obtain images with higher imaging quality, fewer artifacts, and lower noise.

Section: The Conventional Capon Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lamb wave based damage imaging using an adaptive Capon method

Peng,

Xu,

Gao

et al. 2023

“…Liu et al [20] merged the time reversal method with the RAPID algorithm to detect layered damage in composite materials. To address the challenges of anisotropy and mode mixing in the imaging of ultrasonic Lamb waves for damage assessment in anisotropic composite laminates, Wu et al [21] presented a sparse reconstruction imaging method based on the S0 single mode. Wang et al [22] developed a model encompassing Lamb wave generation, propagation, wave-crack linear and nonlinear interactions, and reception, proposing a nonlinear Lamb wave time inversion method for the detection and quantification of fatigue cracks.…”

Section: Introductionmentioning

confidence: 99%

Novel baseline-free ultrasonic Lamb wave defect location method based on path amplitude matching

Li,

Luo,

Zhou

2024

Ultrasonic Lamb wave detection technology constitutes a non-destructive evaluation (NDE) approach extensively employed for the identification of flaws within plate-like structures. The conventional method for detecting and localizing defects in isotropic plate-like structures using ultrasonic Lamb waves relies on baseline signal data. However, the reliability of baseline data as a reference value is diminished due to varying working conditions of the structure. Therefore, to overcome the influence of mismatched baseline data, this paper proposes a novel non-baseline Lamb wave defect detection and localization method. Through simulation and experiment studies, it is discovered that defects at different positions have varied impacts on the amplitude of direct wave-packets under the same propagation path. By eliminating differences in the PZT excitation characteristics of the sensing array (normalized through boundary reflect wave), the direct wave amplitude of multiple sensor pairs in the circular array can be compared and ranked. The paths closest to the location of the damage can be identified, enabling to obtain the defect location information. In this paper, the feasibility and effectiveness of this method has been verified by simulation and practical experiments. The experimental data and imaging results obtained over a four-month period demonstrate that, compared to the traditional baseline localization method, the baseline-free method proposed in this study exhibits a greater ability to resist interference caused by changes in environmental temperature. By increasing the number of sensors from 16 to 32, the positioning accuracy can be significantly improved, reducing the positioning deviation from 13 mm to 0.42 mm. This new non-baseline method based on path amplitude matching demonstrates enhanced practicality within the realm of engineering. Notably, this method holds the potential to be synergistically incorporated and applied in conjunction with various other measurement techniques.

“…Mezil calculated the dispersion curves, numerically studying its frequency dependence on interfacial stiffnesses and the bonding layer thickness [27]. Wu proposed a sparse reconstruction imaging method based on S0 single mode for damage of anisotropic composite laminates [28]. Balvantín studied experimentally and theoretically the effect of loading and unloading cycles on the guided wave propagation parameters [29].…”

Section: Introductionmentioning

confidence: 99%

Evaluating interfacial bonding quality of multilayered structure based on ultrasonic testing technology

Wang

et al. 2023

An ultrasonic evaluation method of interfacial bonding quality from layered structures is proposed for enhancing the testing accuracy. The ultrasonic reflection and transmission characteristic is theoretically analyzed, which focus on the different quality of the single and double bonding interface with spring-type. The reflection coefficient and transmission coefficient mathematic models, which include multiple parameters, are derived from the transfer matrix. Taking the first, second, and the double bonding interface as the research objects, respectively, two types of resonant frequencies have been presented by numerical solving the model, namely, the first type resonance frequency (RFI) and the second type resonance frequency (RFII). The results show that the interval of the RFⅠ is related to medium thickness of the maximum acoustic impedance. Similarly, the interval of the RFⅡ depends on other layers’ thickness. In addition, the transmission coefficient shows a change in different trends with the bonding interface gradually tending to rigid. When the adhesive layer thickness is sufficiently small compared with the wavelength, the reflection coefficient shows many local minima points at a certain frequencies range, the frequency of local minimum point increases with the increase of the stiffness coefficient. The experimental results are in good agreement with the numerical solution results and finite element analysis (FEA) results.