Pub Date : 2025-09-16DOI: 10.1016/j.ndteint.2025.103551
Zhanqiang Xing , Luyun Ding , Weiliang Ji , Shukui Liu , Chenchen Sun , Xiangyu Sun
Compared to traditional ultrasonic probes, piezoelectric micromechanical ultrasound transducer (PMUT) arrays have many advantages in the field of composite flaw detection owing to their small size, good consistency, and high sensitivity. However, in the actual detection process, the problems of low axial resolution and echo overlap significantly hinder the further development of PMUT devices for composite flaw detection. In this study, a broadband (75 %) PMUT with a center frequency of 2 MHz was designed using a multi-size mixing structure. At the same time, based on the acoustic phase flip phenomenon, a correlation coefficient method of translational window signals is proposed, which can accurately identify tiny (50-μm-thick, 1/10 wavelength) delamination defects by calculating the phase difference of the echo front, and successfully breaks through the half-wavelength detection limit. In addition, the C-scan imaging results of the two types of delamination defects demonstrate the capability of the PMUT device and detection algorithm in the detection of delamination defects in composite materials. This above study provides research ideas for the further development of ultrasonic devices in the field of solid micro-sized defect detection.
{"title":"Interfacial delamination detection of multilayer composite structures based on broadband PMUT arrays","authors":"Zhanqiang Xing , Luyun Ding , Weiliang Ji , Shukui Liu , Chenchen Sun , Xiangyu Sun","doi":"10.1016/j.ndteint.2025.103551","DOIUrl":"10.1016/j.ndteint.2025.103551","url":null,"abstract":"<div><div>Compared to traditional ultrasonic probes, piezoelectric micromechanical ultrasound transducer (PMUT) arrays have many advantages in the field of composite flaw detection owing to their small size, good consistency, and high sensitivity. However, in the actual detection process, the problems of low axial resolution and echo overlap significantly hinder the further development of PMUT devices for composite flaw detection. In this study, a broadband (75 %) PMUT with a center frequency of 2 MHz was designed using a multi-size mixing structure. At the same time, based on the acoustic phase flip phenomenon, a correlation coefficient method of translational window signals is proposed, which can accurately identify tiny (50-μm-thick, 1/10 wavelength) delamination defects by calculating the phase difference of the echo front, and successfully breaks through the half-wavelength detection limit. In addition, the C-scan imaging results of the two types of delamination defects demonstrate the capability of the PMUT device and detection algorithm in the detection of delamination defects in composite materials. This above study provides research ideas for the further development of ultrasonic devices in the field of solid micro-sized defect detection.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"158 ","pages":"Article 103551"},"PeriodicalIF":4.5,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-16DOI: 10.1016/j.ndteint.2025.103543
Bernd Köhler, Frank Schubert
It is widely accepted, that nonlinear elastodynamic methods are superior to linear methods in detecting early stages of material deterioration. A number of recently developed methods based on counting spectral peaks are reported to be simple, robust but nevertheless very sensitive to nonlinearities and thus appropriate to indicate early damage. We applied systematically one of the methods, the sideband peak count index (SPC-I), to a series of increasingly damaged carbon fiber reinforced plastic (CFRP) plates. Our data leads to other conclusions. The SPC-I values are influenced by (usually undocumented) variations in the index calculation procedure, which is not acceptable for a robust method. Moreover, the behavior of the index when the ultrasound amplitude is varied excludes material nonlinearity as a direct and significant contributor to the index value. To clarify the apparent contradiction of our results with the previously published statements, it is recommended that (a) our data is re-evaluated by independent researchers and (b) the experiments already published are repeated or (if sufficient data is available) re-evaluated as well.
{"title":"A critical note on the sideband peak count-index technique: Failure for nonlinear damage characterization of impacted CFRP plates","authors":"Bernd Köhler, Frank Schubert","doi":"10.1016/j.ndteint.2025.103543","DOIUrl":"10.1016/j.ndteint.2025.103543","url":null,"abstract":"<div><div>It is widely accepted, that nonlinear elastodynamic methods are superior to linear methods in detecting early stages of material deterioration. A number of recently developed methods based on counting spectral peaks are reported to be simple, robust but nevertheless very sensitive to nonlinearities and thus appropriate to indicate early damage. We applied systematically one of the methods, the sideband peak count index (SPC-I), to a series of increasingly damaged carbon fiber reinforced plastic (CFRP) plates. Our data leads to other conclusions. The SPC-I values are influenced by (usually undocumented) variations in the index calculation procedure, which is not acceptable for a robust method. Moreover, the behavior of the index when the ultrasound amplitude is varied excludes material nonlinearity as a direct and significant contributor to the index value. To clarify the apparent contradiction of our results with the previously published statements, it is recommended that (a) our data is re-evaluated by independent researchers and (b) the experiments already published are repeated or (if sufficient data is available) re-evaluated as well.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"158 ","pages":"Article 103543"},"PeriodicalIF":4.5,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-16DOI: 10.1016/j.ndteint.2025.103550
Yuanyuan Feng , Qi Wu , Yuxi Zhang , Shengming Cui , Ruixin Bao
Although conventional guided-wave-based ultrasonic structural health monitoring (SHM) is paramount for ensuring the safe operation of structural components, the piezoelectric materials used to generate and detect ultrasonic guided waves have the intrinsic issues of electromagnetic interference susceptibility, poor embeddability, and limited multiplexing. To address these issues, an embeddable multi-channel all-optical-fiber acousto-ultrasonic (AOF-AU) system is proposed. A pulsed laser was coupled into specialty optical fibers, and ultrasonic-guided waves were generated from photo-thermal-acoustic conversion. After propagating through the target structure, the ultrasonic wave was detected using a fiber Bragg grating (FBG), which was demodulated using the edge-filtering principle. The control section paired the channel in the optical switch and FBG array and synchronized the ultrasonic excitation and detection to achieve multi-channel SHM. A high-quality carbon fiber reinforced polymer (CFRP) embedded with optical fibers was manufactured; however, a flame-shaped ablation area was observed at the end of the specialty optical fiber. The cross-section of the CFRP did not exhibit a resin-rich area or fiber waviness. The correlation between the characteristics of the optical pulse signal and the ultrasonic wave was clarified under different parameters of the pulsed laser. The ultrasonic signal showed barely changed during continuous monitoring, demonstrating that damage does not accumulate further. In the multi-channel AOF-AU system, the multi-channel capability and strong directionality were demonstrated. In addition, the different attenuations of the ultrasonic waves evaluated in the AOF-AU system enabled easy localization of a hole within the CFRP laminate, demonstrating the capability of the newly proposed system for ultrasonic SHM.
{"title":"Embeddable multi-channel all-optical-fiber acousto-ultrasonic system for damage evaluation of composites","authors":"Yuanyuan Feng , Qi Wu , Yuxi Zhang , Shengming Cui , Ruixin Bao","doi":"10.1016/j.ndteint.2025.103550","DOIUrl":"10.1016/j.ndteint.2025.103550","url":null,"abstract":"<div><div>Although conventional guided-wave-based ultrasonic structural health monitoring (SHM) is paramount for ensuring the safe operation of structural components, the piezoelectric materials used to generate and detect ultrasonic guided waves have the intrinsic issues of electromagnetic interference susceptibility, poor embeddability, and limited multiplexing. To address these issues, an embeddable multi-channel all-optical-fiber acousto-ultrasonic (AOF-AU) system is proposed. A pulsed laser was coupled into specialty optical fibers, and ultrasonic-guided waves were generated from photo-thermal-acoustic conversion. After propagating through the target structure, the ultrasonic wave was detected using a fiber Bragg grating (FBG), which was demodulated using the edge-filtering principle. The control section paired the channel in the optical switch and FBG array and synchronized the ultrasonic excitation and detection to achieve multi-channel SHM. A high-quality carbon fiber reinforced polymer (CFRP) embedded with optical fibers was manufactured; however, a flame-shaped ablation area was observed at the end of the specialty optical fiber. The cross-section of the CFRP did not exhibit a resin-rich area or fiber waviness. The correlation between the characteristics of the optical pulse signal and the ultrasonic wave was clarified under different parameters of the pulsed laser. The ultrasonic signal showed barely changed during continuous monitoring, demonstrating that damage does not accumulate further. In the multi-channel AOF-AU system, the multi-channel capability and strong directionality were demonstrated. In addition, the different attenuations of the ultrasonic waves evaluated in the AOF-AU system enabled easy localization of a hole within the CFRP laminate, demonstrating the capability of the newly proposed system for ultrasonic SHM.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"158 ","pages":"Article 103550"},"PeriodicalIF":4.5,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-15DOI: 10.1016/j.ndteint.2025.103545
Shuang Liu , Huifeng Zheng , Cheng Hang , Baoming Peng , Guoyang Teng , Chenlong Yang
Layered structures have significant difficulties in ultrasonic far-focused pixel-based imaging (FPB) due to the large difference in interlayer acoustic impedance. To enhance the detection resolution and imaging quality of defects in the second layer of layered structures, an improved nonlinear beamforming method for FPB of layered structure defects —— Far-focused Pixel-Based imaging based on Nonlinear beamforming using Circular coherence factor and Baseband Delay-Multiply-and-Sum (CCB-NFPB) is proposed in this paper. Firstly, the spatial coherence of the received signal is introduced through Baseband Delay-Multiply-and-Sum (BB-DMAS) nonlinear beamforming to suppress background noise. By incorporating multiplicative operations between demodulated baseband signals, BB-DMAS introduces nonlinear characteristics that improve robustness to reverberation and signal interference. Then, the circular coherence factor (CCF) constructed using the phase information of the signal is adaptively weighted to further improve the image intensity of deep defect locations, in order to overcome the signal-to-noise ratio (SNR) degradation caused by sound wave propagation attenuation. The experiment is based on the k-wave acoustic field simulation platform to optimize the emission parameters (with 36 sub apertures and a focusing depth of 130 mm). Experimental results demonstrated that CCB-NFPB improved the SNR by 97.7 % compared to the conventional linear beamformed Delay-and-Sum (DAS) method, reduced lateral resolution error between adjacent defects by 55.1 %, and maintained over 93.8 % SNR improvement within the 15–25 mm depth range. The proposed method demonstrates a remarkable ability to suppress interface reflection noise and effectively resolves key challenges in second-layer defect imaging, including limited resolution and pronounced signal attenuation at greater depths. It offers robust performance in accurate defect characterization, effective noise mitigation, and resilience against amplitude degradation.
{"title":"Far-focused pixel-based imaging of defects in layered structures based on improved nonlinear beamforming","authors":"Shuang Liu , Huifeng Zheng , Cheng Hang , Baoming Peng , Guoyang Teng , Chenlong Yang","doi":"10.1016/j.ndteint.2025.103545","DOIUrl":"10.1016/j.ndteint.2025.103545","url":null,"abstract":"<div><div>Layered structures have significant difficulties in ultrasonic far-focused pixel-based imaging (FPB) due to the large difference in interlayer acoustic impedance. To enhance the detection resolution and imaging quality of defects in the second layer of layered structures, an improved nonlinear beamforming method for FPB of layered structure defects —— Far-focused Pixel-Based imaging based on Nonlinear beamforming using Circular coherence factor and Baseband Delay-Multiply-and-Sum (CCB-NFPB) is proposed in this paper. Firstly, the spatial coherence of the received signal is introduced through Baseband Delay-Multiply-and-Sum (BB-DMAS) nonlinear beamforming to suppress background noise. By incorporating multiplicative operations between demodulated baseband signals, BB-DMAS introduces nonlinear characteristics that improve robustness to reverberation and signal interference. Then, the circular coherence factor (CCF) constructed using the phase information of the signal is adaptively weighted to further improve the image intensity of deep defect locations, in order to overcome the signal-to-noise ratio (SNR) degradation caused by sound wave propagation attenuation. The experiment is based on the k-wave acoustic field simulation platform to optimize the emission parameters (with 36 sub apertures and a focusing depth of 130 mm). Experimental results demonstrated that CCB-NFPB improved the SNR by 97.7 % compared to the conventional linear beamformed Delay-and-Sum (DAS) method, reduced lateral resolution error between adjacent defects by 55.1 %, and maintained over 93.8 % SNR improvement within the 15–25 mm depth range. The proposed method demonstrates a remarkable ability to suppress interface reflection noise and effectively resolves key challenges in second-layer defect imaging, including limited resolution and pronounced signal attenuation at greater depths. It offers robust performance in accurate defect characterization, effective noise mitigation, and resilience against amplitude degradation.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"158 ","pages":"Article 103545"},"PeriodicalIF":4.5,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-12DOI: 10.1016/j.ndteint.2025.103548
Heshan Wang, Guoshuang Shui
To evaluate the interfacial debonding damage, this research explores the generation and propagation of Lamb wave-induced quasi-static component (QSC) in the adhesively bonded composite structures based on finite element (FE) simulation and experimental testing. Compared with the second harmonic generation (SHG) of Lamb waves, the QSC method does not require strict phase velocity matching, but only approximate group velocity matching. This characteristic substantially broadens the selectable range of fundamental Lamb wave modes, thereby enhancing the practical applicability of the QSC-based ultrasonic evaluation method. To evaluate the initiation and extension of debonding damage, a micro-crack is introduced in FE simulations. The simulation results demonstrate that QSC has higher sensitivity to the variation of crack length compared with SHG method, and the experimental investigations show a positive correlation between the acoustic nonlinearity parameter (ANP) and the increase in interfacial debonding area. The consistency between FE simulation and experimental data conclusively demonstrates that the QSC method provides a reliable and accurate nondestructive evaluation technique for characterizing interfacial debonding in the adhesively bonded composite structures.
{"title":"Ultrasonic evaluation of interfacial damage in adhesively bonded structure using quasi-static component of Lamb waves","authors":"Heshan Wang, Guoshuang Shui","doi":"10.1016/j.ndteint.2025.103548","DOIUrl":"10.1016/j.ndteint.2025.103548","url":null,"abstract":"<div><div>To evaluate the interfacial debonding damage, this research explores the generation and propagation of Lamb wave-induced quasi-static component (QSC) in the adhesively bonded composite structures based on finite element (FE) simulation and experimental testing. Compared with the second harmonic generation (SHG) of Lamb waves, the QSC method does not require strict phase velocity matching, but only approximate group velocity matching. This characteristic substantially broadens the selectable range of fundamental Lamb wave modes, thereby enhancing the practical applicability of the QSC-based ultrasonic evaluation method. To evaluate the initiation and extension of debonding damage, a micro-crack is introduced in FE simulations. The simulation results demonstrate that QSC has higher sensitivity to the variation of crack length compared with SHG method, and the experimental investigations show a positive correlation between the acoustic nonlinearity parameter (ANP) and the increase in interfacial debonding area. The consistency between FE simulation and experimental data conclusively demonstrates that the QSC method provides a reliable and accurate nondestructive evaluation technique for characterizing interfacial debonding in the adhesively bonded composite structures.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"158 ","pages":"Article 103548"},"PeriodicalIF":4.5,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145061440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-11DOI: 10.1016/j.ndteint.2025.103536
Guanlin Li , Yao Hu , Qun Hao
Shearography is an effective technique for detecting and localizing near-surface defects in engineering materials. However, as critical experimental parameters in shearography, both the loading magnitude and shearing magnitude can lead to localization errors or even misjudgment. Although existing shearography-based approaches have made progress in defect localization, challenges remain in achieving both high localization accuracy and robustness. To address these challenges, we propose a novel framework combining two key innovations: (1) a multi-directional shearography system to separate and eliminate errors caused by shearing magnitude, and (2) a criterion for optimal loading magnitude selection to suppress errors caused by loading magnitude. Using our method, we performed defect localization on a test object containing three types of defects. Experimental results demonstrate that, within a suitable range of loading magnitude, our method achieves a relative error of 3.6 % in the defect area (indicating size accuracy) and an average intersection over union of 0.8156 (reflecting overlap consistency with ground truth). Furthermore, key parameters of multi-directional shearography are analysis, and defects with extreme aspect ratios are localized, demonstrating the superior performance of our method.
{"title":"Multi-directional shearography for high-precision localization of near-surface defects","authors":"Guanlin Li , Yao Hu , Qun Hao","doi":"10.1016/j.ndteint.2025.103536","DOIUrl":"10.1016/j.ndteint.2025.103536","url":null,"abstract":"<div><div>Shearography is an effective technique for detecting and localizing near-surface defects in engineering materials. However, as critical experimental parameters in shearography, both the loading magnitude and shearing magnitude can lead to localization errors or even misjudgment. Although existing shearography-based approaches have made progress in defect localization, challenges remain in achieving both high localization accuracy and robustness. To address these challenges, we propose a novel framework combining two key innovations: (1) a multi-directional shearography system to separate and eliminate errors caused by shearing magnitude, and (2) a criterion for optimal loading magnitude selection to suppress errors caused by loading magnitude. Using our method, we performed defect localization on a test object containing three types of defects. Experimental results demonstrate that, within a suitable range of loading magnitude, our method achieves a relative error of 3.6 % in the defect area (indicating size accuracy) and an average intersection over union of 0.8156 (reflecting overlap consistency with ground truth). Furthermore, key parameters of multi-directional shearography are analysis, and defects with extreme aspect ratios are localized, demonstrating the superior performance of our method.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"158 ","pages":"Article 103536"},"PeriodicalIF":4.5,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-11DOI: 10.1016/j.ndteint.2025.103547
Kang Wang , Lizhuang Cui , Jian Liu , Feng Guo
Water leakage is the most common issue in tunnels, with lining cracks being the direct cause of water ingress. To address the challenge of cracks' thermal characteristics being obscured by water in thermal images, this study established a simulation environment for tunnel water leakage, revealing the temperature field variation patterns of lining leaks. Additionally, the features of cracks in thermal images were enhanced. Using the Kaiyuan Tunnel as a case study, a comprehensive thermal imaging detection method for tunnel water leakage was developed. The crack features in thermal images were segmented, and a location distribution map was generated. The inspection results identified the causes of tunnel water leakage and its distribution density. Furthermore, the correlation between tunnel water leakage, surrounding rock geology, and mountain terrain was established. Finally, maintenance recommendations for the tunnel were proposed. This research provides valuable insights and references for the practical application of thermal imaging detection in tunnel scenarios.
{"title":"Enhanced leak detection in tunnel cracks using thermal imaging: A case study on statistical cause analysis","authors":"Kang Wang , Lizhuang Cui , Jian Liu , Feng Guo","doi":"10.1016/j.ndteint.2025.103547","DOIUrl":"10.1016/j.ndteint.2025.103547","url":null,"abstract":"<div><div>Water leakage is the most common issue in tunnels, with lining cracks being the direct cause of water ingress. To address the challenge of cracks' thermal characteristics being obscured by water in thermal images, this study established a simulation environment for tunnel water leakage, revealing the temperature field variation patterns of lining leaks. Additionally, the features of cracks in thermal images were enhanced. Using the Kaiyuan Tunnel as a case study, a comprehensive thermal imaging detection method for tunnel water leakage was developed. The crack features in thermal images were segmented, and a location distribution map was generated. The inspection results identified the causes of tunnel water leakage and its distribution density. Furthermore, the correlation between tunnel water leakage, surrounding rock geology, and mountain terrain was established. Finally, maintenance recommendations for the tunnel were proposed. This research provides valuable insights and references for the practical application of thermal imaging detection in tunnel scenarios.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"158 ","pages":"Article 103547"},"PeriodicalIF":4.5,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145048527","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-10DOI: 10.1016/j.ndteint.2025.103534
Christian Peyton , Steve Dixon , Ben Dutton , Wilson Vesga , Rachel S. Edwards
It is essential to detect defects in plates, and ultrasonic guided waves offer the potential for detection of defects ranging from porosity in welds, through to larger corrosion patches. Shear-horizontal (SH) waves generated by electromagnetic acoustic transducers (EMATs) have previously been shown to interact with both types of defect, with the reflection properties dependent on the defect geometry and the wavelength and wavemode chosen. This paper investigates the behaviour of the mode converted reflections that occur when an incident SH0 wave interacts with a defect in a plate. The properties of the reflected mode converted fundamental symmetric Lamb wave, S0, are shown to depend on the defect width, length and depth, which determine the angle at which a peak reflection occurs. This paper aims to develop fundamental understanding of the behaviour, showing that the defect width reflection behaviour follows a modified single-slit-diffraction behaviour, while the defect length dependence is due to interference between waves reflected from the front and back faces of the defect. Finite element simulations are primarily used, and verified experimentally. The S0 reflection is small, but results could be combined with analysis of SH0 reflections, enabling a higher probability of detection for small (mm-sized) defects.
{"title":"Mode conversion of the fundamental shear horizontal wave at a defect","authors":"Christian Peyton , Steve Dixon , Ben Dutton , Wilson Vesga , Rachel S. Edwards","doi":"10.1016/j.ndteint.2025.103534","DOIUrl":"10.1016/j.ndteint.2025.103534","url":null,"abstract":"<div><div>It is essential to detect defects in plates, and ultrasonic guided waves offer the potential for detection of defects ranging from porosity in welds, through to larger corrosion patches. Shear-horizontal (SH) waves generated by electromagnetic acoustic transducers (EMATs) have previously been shown to interact with both types of defect, with the reflection properties dependent on the defect geometry and the wavelength and wavemode chosen. This paper investigates the behaviour of the mode converted reflections that occur when an incident SH0 wave interacts with a defect in a plate. The properties of the reflected mode converted fundamental symmetric Lamb wave, S0, are shown to depend on the defect width, length and depth, which determine the angle at which a peak reflection occurs. This paper aims to develop fundamental understanding of the behaviour, showing that the defect width reflection behaviour follows a modified single-slit-diffraction behaviour, while the defect length dependence is due to interference between waves reflected from the front and back faces of the defect. Finite element simulations are primarily used, and verified experimentally. The S0 reflection is small, but results could be combined with analysis of SH0 reflections, enabling a higher probability of detection for small (mm-sized) defects.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"158 ","pages":"Article 103534"},"PeriodicalIF":4.5,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-08DOI: 10.1016/j.ndteint.2025.103544
Wang Xiao , Maciej Radzieński , Maosen Cao , Jianping Zhou , Wei Xu , Zhongqing Su , Wiesław Ostachowicz
Delaminations in composite laminates, though often barely visible, can compromise the integrity and safety of composite structures. Over the past decade, linear steady-state wavefields (LSWs) have emerged with attractive merits for imaging delaminations. However, LSWs struggle to effectively image small delaminations as their stiffnesses can hardly be affected. In contrast, contact-induced nonlinearity, arising from the breathing behaviour of delamination interfaces, can provide nonlinear delamination features in nonlinear steady-state wavefields (NSWs), offering the potential to provide complete configurations of delaminations. This study focuses on extracting nonlinear delamination features using a nonlinear perturbation to an NSW. The perturbation, which exists exclusively within the delamination region, is virtually treated as a multi-tone harmonic excitation source, serving as an ideal index for imaging delaminations. Particularly, a baseline-free method is utilized to reconstruct the nonlinear perturbation using the NSW data in a statistical manner. The capability of the approach is validated experimentally on a glass fiber reinforced polymer laminated plate with multiple local delaminations, which were induced by Teflon inserts, low-speed impacts, and local heating. A PZT actuator is centrally mounted on the plate to generate a single-tone harmonic excitation, and simultaneously, a scanning laser Doppler vibrometer measures the LSW and NSW of the plate. The experimental results reveal that the NSW can provide additional nonlinear delamination features that are scarcely carried in the LSW. Beyond three large thermal delaminations, several small delaminations induced by the Teflon inserts and impacts can also be graphically characterized, allowing for comprehensive imaging of the multiple delaminations.
{"title":"Imaging delaminations in composite laminates via linear-to-nonlinear steady-state wavefields","authors":"Wang Xiao , Maciej Radzieński , Maosen Cao , Jianping Zhou , Wei Xu , Zhongqing Su , Wiesław Ostachowicz","doi":"10.1016/j.ndteint.2025.103544","DOIUrl":"10.1016/j.ndteint.2025.103544","url":null,"abstract":"<div><div>Delaminations in composite laminates, though often barely visible, can compromise the integrity and safety of composite structures. Over the past decade, linear steady-state wavefields (LSWs) have emerged with attractive merits for imaging delaminations. However, LSWs struggle to effectively image small delaminations as their stiffnesses can hardly be affected. In contrast, contact-induced nonlinearity, arising from the breathing behaviour of delamination interfaces, can provide nonlinear delamination features in nonlinear steady-state wavefields (NSWs), offering the potential to provide complete configurations of delaminations. This study focuses on extracting nonlinear delamination features using a nonlinear perturbation to an NSW. The perturbation, which exists exclusively within the delamination region, is virtually treated as a multi-tone harmonic excitation source, serving as an ideal index for imaging delaminations. Particularly, a baseline-free method is utilized to reconstruct the nonlinear perturbation using the NSW data in a statistical manner. The capability of the approach is validated experimentally on a glass fiber reinforced polymer laminated plate with multiple local delaminations, which were induced by Teflon inserts, low-speed impacts, and local heating. A PZT actuator is centrally mounted on the plate to generate a single-tone harmonic excitation, and simultaneously, a scanning laser Doppler vibrometer measures the LSW and NSW of the plate. The experimental results reveal that the NSW can provide additional nonlinear delamination features that are scarcely carried in the LSW. Beyond three large thermal delaminations, several small delaminations induced by the Teflon inserts and impacts can also be graphically characterized, allowing for comprehensive imaging of the multiple delaminations.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"158 ","pages":"Article 103544"},"PeriodicalIF":4.5,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-29DOI: 10.1016/j.ndteint.2025.103535
Ekaterina Iakovleva, David Roué, Sylvain Chatillon
Ultrasonic phased-array technology is widely used in many NDT (Non-Destructive Testing) fields. Its ability to electronically steer and focus ultrasonic beams allows for comprehensive inspections with improved accuracy. However, the performances of an ultrasonic inspection may be degraded when the component being inspected exhibits an uneven surface. If the surface geometry is unknown, phased array technology is unable to correct the perturbations of acoustical beams using array settings. In this work, we present a new immersion adaptive inspection technique of large and complex-shaped components using a matrix array. In this approach, first, the unknown surface geometry of the inspected component is reconstructed from a series of 2D TFM images collected using only one row and one column of the matrix array acting as two independent orthogonal 1D arrays, in conjunction with mechanical 2D scanning. At this stage, the recorded 2D images are combined into a single wide-view 3D surface image by rotational SAFT algorithm, a simplified version of the standard SAFT method. The desired surface is extracted from the resulting image using an automatic global thresholding method. Then, based on the reconstructed surface and given the inspection probe trajectory, adapted focal laws to inspect the interior of the component are computed and applied at every location of the probe to correct the effect of the surface. The capabilities of the proposed inspection technique are illustrated by various simulated and experimental results carried out in a water tank. Its advantages and drawbacks will be discussed.
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