IWSHM 2017: Damage-scattered wave extraction in an integral stiffened isotropic plate: a baseline-subtraction-free approach

He, Jiaze; Leser, Patrick E.; Leser, William P.; Fang, Yuan

doi:10.1177/1475921718769232

Cited by 6 publications

(9 citation statements)

References 70 publications

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“…In some complex structures, baseline-subtraction-free methods can be used to extract the damage-scattered signal. 77 However, it would still be more convenient if the baseline signals are not needed for imaging. Since only a single source was used in each excitation while the damage-scattered signals existed for all of the excitations, inversions might be possible using all of the received signals.…”

Section: Resultsmentioning

confidence: 99%

Guided wave tomography based on least-squares reverse-time migration

Rocha

Sava

2019

Structural Health Monitoring

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A key to successful damage diagnostics and quantification is damage imaging through ultrasonic guided wave tomography. We propose the implementation of least-squares reverse-time migration in a circular array for damage imaging in an aluminum plate. The theory of least-squares reverse-time migration is formulated for guided wave applications along with the summary of an efficient optimization algorithm: the conjugate gradient method. Numerical simulation and laboratory experiments are used to evaluate its performance with a circular array setup. In order to improve the data processing efficiency, the concept of using a limited number of actuators but a relatively large number of sensors is tested. Studies are conducted on three numerical cases, including a rectangular-shaped damage site, a complex-shaped damage site, and six other damage sites varying in size. As an inversion-based method, least-squares reverse-time migration shows significantly improved shape reconstruction with the amplitude quantification capability, compared to conventional reverse-time migration. Our experimental data are generated by piezoelectric wafers as actuators, measured by a scanning laser Doppler vibrometer to form a circular array on an aluminum plate, with a rectangular notch located in the inner region of the array. The damage images using experimental data show consistency in both the simulations using Born scattering and in altered material properties in the damaged region. According to the comparison, least-squares reverse-time migration for guided wave tomography is a promising technology to provide high-resolution large area damage imaging for plate-like structures.

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Section: Resultsmentioning

confidence: 99%

Guided wave tomography based on least-squares reverse-time migration

Rocha

Sava

2019

Structural Health Monitoring

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“…He et al 21 proposed the use of a linear Radon transform (LRT)-based extraction algorithm as a BSF damage detection approach. Promising initial results were obtained using a LRT, which converts the signals to a 2-dimensional intercept-slowness ( τ − q ) domain where linear events are compressed into a point-like region.…”

Section: Introductionmentioning

confidence: 99%

“…19,20 These methods accurately image damage sites based on solver-based inversion but the valid imaging results require accurate modeling, which might be nontrivial to achieve for complex structures. He et al 21 proposed the use of a linear Radon transform (LRT)-based extraction algorithm as a BSF damage detection approach. Promising initial results were obtained using a LRT, which converts the signals to a 2-dimensional intercept-slowness ðt À qÞ domain where linear events are compressed into a point-like region.…”

Section: Introductionmentioning

confidence: 99%

Apex-shifted Radon transform for baseline-subtraction-free (BSF) damage scattered wave extraction

Loshelder

Aktharuzzaman

et al. 2023

Structural Health Monitoring

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In ultrasonic structural health monitoring (SHM) and nondestructive evaluation (NDE), the scattered waves caused by damage sites and defects are the key to damage diagnosis. However, structural components and boundaries also interact with traveling waves, creating events that can bury damage scattered waves. The baseline subtraction method, which directly subtracts the waveform of a damage signal from that of a pristine baseline signal, is a common processing technique to separate these damage scattered waves. However, baseline subtraction is less effective when a component is measured in different environmental/loading conditions from when its baseline was recorded. For instance, baseline subtraction can be ineffective in aerospace structural parts because such parts expect significant and routine changes in ambient temperature, pressure, and humidity. To overcome the limitations of baseline subtraction, this paper proposes to develop an spex-shifted Radon transform (ASRT)-based damage scattered event extraction technique without baseline subtraction. Our proposed ASRT method converts the original time-space [Formula: see text] domain signals to a time delay–curvature–apex offset [Formula: see text] domain, which targets specific geometries of scattered/reflected waves in the [Formula: see text] domain and compresses them into a single point-like region in the new domain. In this domain, identifying and isolating targeted events becomes significantly easier. To benchmark the performance of this baseline-subtraction-free (BSF) method, ASRT is applied for signals acquired from (1) spectral finite element-based simulations to scan a water-immersed steel specimen (2) 3-D wave simulations in a bent aluminum plate, and (3) a full matrix capture for experimentally scanning a high-density polyethylene (HDPE) with multiple holes. The goal in each case is to target and separate events of interest from the original signals using the proposed algorithm. The results suggest the ASRT method is effective as a damage scattered wave extraction tool for ultrasonic SHM and NDE.

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“…Recently, considerable literature has focused on baseline-free approaches with signal processing techniques, such as wavelet transform [ 33 , 34 ], random transform [ 35 ], Gaussian smoothing [ 36 , 37 ], and dictionary learning [ 38 , 39 ]. It is worth noting that Zhou et al [ 40 ] proposed a method to separate multiple modes of Lamb waves by reconstructing pure mode basis signals calculated upon phase velocity and group velocity.…”

Section: Introductionmentioning

confidence: 99%

A Novel Baseline-Free Damage Detection Method Based on Path Scanning of Lamb Waves Using Mobile Transducers

Yuan

Zhou

et al. 2022

Sensors

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The baseline-free damage detection method of Lamb waves has the potential to obtain damage information efficiently in plate structures through damage scattering signals. However, the missing detection of damage occurs occasionally due to the angular scattering characteristic of Lamb waves. To solve this problem, a novel baseline-free damage detection approach based on path scanning at the detection region edges using mobile piezoelectric transducers is proposed herein. Several sensing points carrying separated damage scattering signals were picked out from the scanning paths. By removing the direct and boundary reflected signals, the damage signals were extracted and exported to a delay-and-sum imaging method to locate the damage. Two experiments with and without mobile transducers were conducted to validate the proposed method on an aluminum plate with artificially fabricated crack-like damage. The results show that the proposed baseline-free approach can locate the crack-like damage with high accuracy and efficiency and avoid potential loss of damage information. The proposed baseline-free method provides a novel and practical damage detection approach when considering the angular-dependent scattering characteristic of Lamb waves and can enhance the credibility of results in damage detection.

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IWSHM 2017: Damage-scattered wave extraction in an integral stiffened isotropic plate: a baseline-subtraction-free approach

Cited by 6 publications

References 70 publications

Guided wave tomography based on least-squares reverse-time migration

Guided wave tomography based on least-squares reverse-time migration

Apex-shifted Radon transform for baseline-subtraction-free (BSF) damage scattered wave extraction

A Novel Baseline-Free Damage Detection Method Based on Path Scanning of Lamb Waves Using Mobile Transducers

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