Pub Date : 2025-12-08DOI: 10.1016/j.ndteint.2025.103623
Zhichao Li, Guichao Huang, Runjie Yang, Xuesong Wang, Chaoran Deng
Electromagnetic acoustic transducers (EMATs) suffer from inherently low transduction efficiency. Recent studies have demonstrated that the horizontal magnetic fields can significantly enhance the signal amplitude of Lorentz force-based EMATs. However, conventional analytical models primarily account for the effects of the vertical magnetic fields, while overlooking the excitation contribution of the horizontal magnetic fields, thereby limiting efforts to improve EMAT performance. In this work, the electromagnetic ultrasonic testing process using Rayleigh waves is systematically divided into three stages: excitation, propagation, and reception. Theoretical models are developed for each stage. Based on this framework, an analytical model incorporating both the vertical and horizontal magnetic fields is established. Experimental results from various coil configurations demonstrate that the proposed theoretical model can accurately compute the ultrasonic signals within the test specimen. Furthermore, the analytical model is employed to investigate the effect of magnet width on the amplitude and distortion level of the received signal. The findings reveal that when the magnet width is equal to the overall width of the coil, the received signal achieves the maximum amplitude with relatively low distortion.
{"title":"Analytical modeling and analysis of Rayleigh-wave EMATs considering both the horizontal and vertical magnetic fields","authors":"Zhichao Li, Guichao Huang, Runjie Yang, Xuesong Wang, Chaoran Deng","doi":"10.1016/j.ndteint.2025.103623","DOIUrl":"10.1016/j.ndteint.2025.103623","url":null,"abstract":"<div><div>Electromagnetic acoustic transducers (EMATs) suffer from inherently low transduction efficiency. Recent studies have demonstrated that the horizontal magnetic fields can significantly enhance the signal amplitude of Lorentz force-based EMATs. However, conventional analytical models primarily account for the effects of the vertical magnetic fields, while overlooking the excitation contribution of the horizontal magnetic fields, thereby limiting efforts to improve EMAT performance. In this work, the electromagnetic ultrasonic testing process using Rayleigh waves is systematically divided into three stages: excitation, propagation, and reception. Theoretical models are developed for each stage. Based on this framework, an analytical model incorporating both the vertical and horizontal magnetic fields is established. Experimental results from various coil configurations demonstrate that the proposed theoretical model can accurately compute the ultrasonic signals within the test specimen. Furthermore, the analytical model is employed to investigate the effect of magnet width on the amplitude and distortion level of the received signal. The findings reveal that when the magnet width is equal to the overall width of the coil, the received signal achieves the maximum amplitude with relatively low distortion.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"159 ","pages":"Article 103623"},"PeriodicalIF":4.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145747413","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 : 2025-12-05DOI: 10.1016/j.ndteint.2025.103622
Edmund Jones , Catrin M. Davies , Joseph Corcoran
A feasibility study into utilising Rayleigh surface waves for sizing regions of discontinuous creep crack damage in compact tension laboratory tests is presented. The method relies on the efficient Rayleigh surface to shear bulk wave mode conversion (and vice versa) at discontinuous surfaces, in a process referred to as ‘skipping’ in this paper. A Finite Element study is presented to demonstrate the skipping behaviour. In order to utilise the Rayleigh wave for creep crack growth measurements, a novel experimental procedure has been developed that enables in situ measurements at elevated temperature. The approach uses waveguides that transmit shear guided waves from ambient conditions to the sample which is inside a furnace. The waveguides are dry-coupled to the corner edges of the compact tension sample, the shear guided waves excite Rayleigh waves which then propagate around the crack tip. By monitoring the time-of-flight of the ultrasound the damaged region can be sized. Results of a creep crack growth experiment are shown and crack size estimates from x-ray computed tomography (XCT), direct current potential drop (DCPD) and the Rayleigh wave techniques are compared. The direct current potential drop measurements vastly underestimates the maximum extent of the damaged region, estimating 0.38 mm in contrast to the 1.40 mm measured by XCT, as the discontinuous defects are not an effective impediment to electrical current. The Rayleigh wave technique estimates a far more accurate 1.27 mm.
{"title":"A skipping Rayleigh wave technique for discontinuous creep crack sizing at high temperature","authors":"Edmund Jones , Catrin M. Davies , Joseph Corcoran","doi":"10.1016/j.ndteint.2025.103622","DOIUrl":"10.1016/j.ndteint.2025.103622","url":null,"abstract":"<div><div>A feasibility study into utilising Rayleigh surface waves for sizing regions of discontinuous creep crack damage in compact tension laboratory tests is presented. The method relies on the efficient Rayleigh surface to shear bulk wave mode conversion (and vice versa) at discontinuous surfaces, in a process referred to as ‘skipping’ in this paper. A Finite Element study is presented to demonstrate the skipping behaviour. In order to utilise the Rayleigh wave for creep crack growth measurements, a novel experimental procedure has been developed that enables in situ measurements at elevated temperature. The approach uses waveguides that transmit shear guided waves from ambient conditions to the sample which is inside a furnace. The waveguides are dry-coupled to the corner edges of the compact tension sample, the shear guided waves excite Rayleigh waves which then propagate around the crack tip. By monitoring the time-of-flight of the ultrasound the damaged region can be sized. Results of a creep crack growth experiment are shown and crack size estimates from x-ray computed tomography (XCT), direct current potential drop (DCPD) and the Rayleigh wave techniques are compared. The direct current potential drop measurements vastly underestimates the maximum extent of the damaged region, estimating 0.38 mm in contrast to the 1.40 mm measured by XCT, as the discontinuous defects are not an effective impediment to electrical current. The Rayleigh wave technique estimates a far more accurate 1.27 mm.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"159 ","pages":"Article 103622"},"PeriodicalIF":4.5,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145747416","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 : 2025-12-03DOI: 10.1016/j.ndteint.2025.103611
D. Kanzler , G. Olm , A. Friedrich , M. Selch
The requirements for using AI algorithms are highly stringent for safety-critical and high-risk applications, such as in the field of non-destructive testing (NDT). Furthermore, there is a regulatory need for conclusive metrics to evaluate AI for high-risk applications. This article introduces a process for evaluating AI used in NDT methods. Based on a commonly used AI evaluation metric adapted for the NDT field, the evaluation aligns with the well-known NDT reliability processes. This evaluation process is applied to analyzing eddy current (ET) data in rail inspection. The aim is to quantify the capability of AI-supported data evaluation against that of the testing setup itself. However, the available real-world dataset of rail inspection data was insufficient for training, validation and demonstrating the reliability of the ET process and AI. To address this, simulated ET data was used to generate a large dataset for evaluation purposes. Using this simulated data, a reference probability of detection (POD) curve was created to provide a benchmark for assessing the performance of the AI using a newly introduced metric called Reliability Metric Score (RESa). The AI model analyzed ET data for crack-like defects. The results were then evaluated and compared to the reference POD. This article explores the evaluation process, highlighting potential misinterpretations and situations where an operator’s judgment is necessary to determine the effectiveness of the AI model in specific cases. This process revealed different regions of interest, which are very useful for further assessment of the AI process and continued development.
{"title":"Evaluation of AI for Eddy Current testing according to the reliability framework for rail inspection","authors":"D. Kanzler , G. Olm , A. Friedrich , M. Selch","doi":"10.1016/j.ndteint.2025.103611","DOIUrl":"10.1016/j.ndteint.2025.103611","url":null,"abstract":"<div><div>The requirements for using AI algorithms are highly stringent for safety-critical and high-risk applications, such as in the field of non-destructive testing (NDT). Furthermore, there is a regulatory need for conclusive metrics to evaluate AI for high-risk applications. This article introduces a process for evaluating AI used in NDT methods. Based on a commonly used AI evaluation metric adapted for the NDT field, the evaluation aligns with the well-known NDT reliability processes. This evaluation process is applied to analyzing eddy current (ET) data in rail inspection. The aim is to quantify the capability of AI-supported data evaluation against that of the testing setup itself. However, the available real-world dataset of rail inspection data was insufficient for training, validation and demonstrating the reliability of the ET process and AI. To address this, simulated ET data was used to generate a large dataset for evaluation purposes. Using this simulated data, a reference probability of detection (POD) curve was created to provide a benchmark for assessing the performance of the AI using a newly introduced metric called Reliability Metric Score (RESa). The AI model analyzed ET data for crack-like defects. The results were then evaluated and compared to the reference POD. This article explores the evaluation process, highlighting potential misinterpretations and situations where an operator’s judgment is necessary to determine the effectiveness of the AI model in specific cases. This process revealed different regions of interest, which are very useful for further assessment of the AI process and continued development.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"159 ","pages":"Article 103611"},"PeriodicalIF":4.5,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691396","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 : 2025-12-03DOI: 10.1016/j.ndteint.2025.103617
Jörg Rehbein , Sebastian-Johannes Lorenz , Dominik O.W. Hirschberg , Philipp A. Rauschnabel , Jens Holtmannspötter , Bernd Valeske
Current ultrasonic testing processes for aircraft inspection remain largely manual and non-digitalized. Among the most promising innovations for effective digitalization is the use of Augmented Reality, aligning with NDE 4.0 trends. Despite initial developments, advantages are merely theoretical, as research exploring real-world usage by domain experts remains scarce. Against this backdrop, this paper presents two consecutive, qualitative studies where NDT experts explored and evaluated a prototype system developed in prior works. The studies were designed to elicit early, indicative insights and actively involve practitioners in the development process. In the second study, inspectors used both the conventional and the new system to reflect on their experiences and assess how these shaped their performance. Despite the early stage of the Augmented Reality system, expert feedback and comparative evaluation were positive and encouraging. Reported advantages included increased speed, ease of use, improved focus, and enhanced documentation. With optimization areas identified, the system, once matured, may substantially outperform traditional methods. This research contributes to NDE 4.0 by clarifying user-centered requirements and reinforcing the importance of practitioner engagement during the digital transformation of inspection workflows.
{"title":"Digitalization of Ultrasonic Non-Destructive Testing Using Augmented Reality: An Expert Evaluation","authors":"Jörg Rehbein , Sebastian-Johannes Lorenz , Dominik O.W. Hirschberg , Philipp A. Rauschnabel , Jens Holtmannspötter , Bernd Valeske","doi":"10.1016/j.ndteint.2025.103617","DOIUrl":"10.1016/j.ndteint.2025.103617","url":null,"abstract":"<div><div>Current ultrasonic testing processes for aircraft inspection remain largely manual and non-digitalized. Among the most promising innovations for effective digitalization is the use of Augmented Reality, aligning with NDE 4.0 trends. Despite initial developments, advantages are merely theoretical, as research exploring real-world usage by domain experts remains scarce. Against this backdrop, this paper presents two consecutive, qualitative studies where NDT experts explored and evaluated a prototype system developed in prior works. The studies were designed to elicit early, indicative insights and actively involve practitioners in the development process. In the second study, inspectors used both the conventional and the new system to reflect on their experiences and assess how these shaped their performance. Despite the early stage of the Augmented Reality system, expert feedback and comparative evaluation were positive and encouraging. Reported advantages included increased speed, ease of use, improved focus, and enhanced documentation. With optimization areas identified, the system, once matured, may substantially outperform traditional methods. This research contributes to NDE 4.0 by clarifying user-centered requirements and reinforcing the importance of practitioner engagement during the digital transformation of inspection workflows.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"159 ","pages":"Article 103617"},"PeriodicalIF":4.5,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145747415","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 : 2025-12-02DOI: 10.1016/j.ndteint.2025.103615
Yanmin Sun , Yu Han , Lei Li , Xiaoqi Xi , Xuejing Lu , Siyu Tan , Linlin Zhu , Yuan Zhang , Bin Yan
Cone-beam computed laminography (CL) is an X-ray three-dimensional imaging technique designed for large plate-shaped objects. However, the commonly used circular-trajectory CL, featuring a tilted rotation axis, results in missing imaging data and leads to aliasing artifacts in reconstructed images. This study proposes spherical helical computed laminography (SHCL), a novel imaging approach that addresses CL data deficiencies and enhances image reconstruction quality. SHCL is achieved by progressively reducing the tilt angle of the rotation axis during circular trajectory rotation, allowing supplementary data acquisition from small tilt angles and significantly mitigating CL data loss. In commonly used CL imaging configurations with tilt angles ranging from 10° to 45°, SHCL can recover 43 %–69 % of the missing data of circular trajectory CL. This study develops an improved FDK reconstruction algorithm to accommodate the spherical helical trajectory of SHCL. Experimental results demonstrate that SHCL effectively reduces aliasing artifacts in CL imaging. The SHCL trajectory is simple to implement and does not introduce additional scanning workload, making it practical for real-world applications.
{"title":"Spherical helical trajectory CL: An improved strategy for circular trajectory cone-beam CL imaging","authors":"Yanmin Sun , Yu Han , Lei Li , Xiaoqi Xi , Xuejing Lu , Siyu Tan , Linlin Zhu , Yuan Zhang , Bin Yan","doi":"10.1016/j.ndteint.2025.103615","DOIUrl":"10.1016/j.ndteint.2025.103615","url":null,"abstract":"<div><div>Cone-beam computed laminography (CL) is an X-ray three-dimensional imaging technique designed for large plate-shaped objects. However, the commonly used circular-trajectory CL, featuring a tilted rotation axis, results in missing imaging data and leads to aliasing artifacts in reconstructed images. This study proposes spherical helical computed laminography (SHCL), a novel imaging approach that addresses CL data deficiencies and enhances image reconstruction quality. SHCL is achieved by progressively reducing the tilt angle of the rotation axis during circular trajectory rotation, allowing supplementary data acquisition from small tilt angles and significantly mitigating CL data loss. In commonly used CL imaging configurations with tilt angles ranging from 10° to 45°, SHCL can recover 43 %–69 % of the missing data of circular trajectory CL. This study develops an improved FDK reconstruction algorithm to accommodate the spherical helical trajectory of SHCL. Experimental results demonstrate that SHCL effectively reduces aliasing artifacts in CL imaging. The SHCL trajectory is simple to implement and does not introduce additional scanning workload, making it practical for real-world applications.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"159 ","pages":"Article 103615"},"PeriodicalIF":4.5,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691400","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 : 2025-12-02DOI: 10.1016/j.ndteint.2025.103613
Fuqiang Yang , Le Wang , Kuidong Huang , Shijie Chai , Zhixiang Li
Scatter severely degrades cone-beam computed tomography (CBCT) images, particularly in scans of high-density industrial components, where blur and shading artifacts hinder metrological evaluation. We propose an LSTM-residual network with an attention module to enhance cross-layer feature propagation. An attention module further improves convolutional neural network efficiency for image feature processing. The core approach estimates the scatter-to-primary ratio (SPR)—a metric reflecting scatter photon distribution influenced by material structures—using raw projection data to generate artifact-free images. By eliminating low-frequency scatter from preliminary observations, the network robustly mitigates scattering effects. Experimental validation with diverse industrial components—an aluminum stepped shaft, a titanium alloy sleeve, and a steel hollow cylinder—shows substantial image quality improvements. Comparative analysis reveals CNR improvements of 22 %, 33 %, and 52, and AG improvements of 46 %, 38 %, and 30 % for the three components, respectively. These results demonstrate the method's effectiveness in enhancing CBCT image clarity and reducing scatter-induced blur, highlighting its utility for industrial non-destructive testing.
{"title":"Application of a dense block connection network to SPR prediction for artifact reduction in X-ray computed tomography","authors":"Fuqiang Yang , Le Wang , Kuidong Huang , Shijie Chai , Zhixiang Li","doi":"10.1016/j.ndteint.2025.103613","DOIUrl":"10.1016/j.ndteint.2025.103613","url":null,"abstract":"<div><div>Scatter severely degrades cone-beam computed tomography (CBCT) images, particularly in scans of high-density industrial components, where blur and shading artifacts hinder metrological evaluation. We propose an LSTM-residual network with an attention module to enhance cross-layer feature propagation. An attention module further improves convolutional neural network efficiency for image feature processing. The core approach estimates the scatter-to-primary ratio (SPR)—a metric reflecting scatter photon distribution influenced by material structures—using raw projection data to generate artifact-free images. By eliminating low-frequency scatter from preliminary observations, the network robustly mitigates scattering effects. Experimental validation with diverse industrial components—an aluminum stepped shaft, a titanium alloy sleeve, and a steel hollow cylinder—shows substantial image quality improvements. Comparative analysis reveals CNR improvements of 22 %, 33 %, and 52, and AG improvements of 46 %, 38 %, and 30 % for the three components, respectively. These results demonstrate the method's effectiveness in enhancing CBCT image clarity and reducing scatter-induced blur, highlighting its utility for industrial non-destructive testing.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"159 ","pages":"Article 103613"},"PeriodicalIF":4.5,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691399","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 : 2025-12-01DOI: 10.1016/j.ndteint.2025.103616
Han Yan , Long Chao , Liu Zefang , Tan Chuandong , Zhou Jianing , Tan Hui , Duan Liming
Sparse-angle scanning can achieve rapid detection of laminated cells by the computed tomography (CT). Typically, sparse-angle scanning uses equiangular sparse angle to scan the object, which may overlook information-rich regions of the internal structure, leading to partial structural loss of the reconstructed images. This paper proposes a non-uniform sparse scanning angle selection method by analysing the discrepancies between the full sinograms and the equiangular sparse sinograms. Firstly, the equiangular sparse sinograms are obtained by an equiangular sparse operator applied to the full sinograms of the laminated cells. Then, the sinograms error curve is obtained by comparing the full sinograms with the equiangular sparse sinograms. Finally, a scanning angle selection model is designed, which can select scanning angles. The optimal experiment results show that our method increases PSNR by 3.7053 and improves SSIM by 0.1797. These results demonstrate that our method improves the quality of CT images while using the same number of scanning angles. Our method offers a novel idea for obtaining clearer CT reconstruction image under CT rapid scanning.
{"title":"Non-uniform scan angle selection for detecting cells via CT","authors":"Han Yan , Long Chao , Liu Zefang , Tan Chuandong , Zhou Jianing , Tan Hui , Duan Liming","doi":"10.1016/j.ndteint.2025.103616","DOIUrl":"10.1016/j.ndteint.2025.103616","url":null,"abstract":"<div><div>Sparse-angle scanning can achieve rapid detection of laminated cells by the computed tomography (CT). Typically, sparse-angle scanning uses equiangular sparse angle to scan the object, which may overlook information-rich regions of the internal structure, leading to partial structural loss of the reconstructed images. This paper proposes a non-uniform sparse scanning angle selection method by analysing the discrepancies between the full sinograms and the equiangular sparse sinograms. Firstly, the equiangular sparse sinograms are obtained by an equiangular sparse operator applied to the full sinograms of the laminated cells. Then, the sinograms error curve is obtained by comparing the full sinograms with the equiangular sparse sinograms. Finally, a scanning angle selection model is designed, which can select scanning angles. The optimal experiment results show that our method increases PSNR by 3.7053 and improves SSIM by 0.1797. These results demonstrate that our method improves the quality of CT images while using the same number of scanning angles. Our method offers a novel idea for obtaining clearer CT reconstruction image under CT rapid scanning.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"159 ","pages":"Article 103616"},"PeriodicalIF":4.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691397","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}
Detecting the cure quality of adhesive in an adhesively bonded composite joint is crucial, as improper curing of adhesive in critical structural joints may compromise performance, durability, and service life. Since the composite adherend materials being bonded have poor thermal conductivity, ensuring that the adhesive reaches a proper cure temperature throughout the bonded region is challenging. While a large body of work exists on in-situ cure monitoring using thermocouples, dielectric, and other sensing elements, utilizing these sensing systems without compromising the adhesive layer is often challenging. Here, a frequency domain, non-destructive, post-cure assessment method has been explored using Broadband Dielectric Spectroscopy (BbDS) over 0.1Hz to 0.1 MHz range, which can identify whether the adhesive has appropriately been cured or not without exposing the bond. Bonded adhesive composite samples in lap-shear configuration with different levels of cure were manufactured by controlling the exposure time to the cure temperature. The stages of cure were verified using a Differential Scanning Calorimeter (DSC) and Fourier Transform Infrared Spectroscopy (FTIR). Dielectric spectroscopy revealed significant differences in the Dielectric Relaxation Strength (DRS) with different levels of cure. Mechanical testing of bonds was carried out and a proportionate correlation was observed with degree of cure of the adhesive. The kinetics of cure mechanisms were also studied in a temperature-frequency dependent Dielectric Spectroscopy.
{"title":"Non-destructive adhesive cure assessment in carbon fiber reinforced composites using dielectric spectroscopy","authors":"Minhazur Rahman , Monjur Morshed Rabby , Vamsee Vadlamudi , Rassel Raihan","doi":"10.1016/j.ndteint.2025.103621","DOIUrl":"10.1016/j.ndteint.2025.103621","url":null,"abstract":"<div><div>Detecting the cure quality of adhesive in an adhesively bonded composite joint is crucial, as improper curing of adhesive in critical structural joints may compromise performance, durability, and service life. Since the composite adherend materials being bonded have poor thermal conductivity, ensuring that the adhesive reaches a proper cure temperature throughout the bonded region is challenging. While a large body of work exists on in-situ cure monitoring using thermocouples, dielectric, and other sensing elements, utilizing these sensing systems without compromising the adhesive layer is often challenging. Here, a frequency domain, non-destructive, post-cure assessment method has been explored using Broadband Dielectric Spectroscopy (BbDS) over 0.1Hz to 0.1 MHz range, which can identify whether the adhesive has appropriately been cured or not without exposing the bond. Bonded adhesive composite samples in lap-shear configuration with different levels of cure were manufactured by controlling the exposure time to the cure temperature. The stages of cure were verified using a Differential Scanning Calorimeter (DSC) and Fourier Transform Infrared Spectroscopy (FTIR). Dielectric spectroscopy revealed significant differences in the Dielectric Relaxation Strength (DRS) with different levels of cure. Mechanical testing of bonds was carried out and a proportionate correlation was observed with degree of cure of the adhesive. The kinetics of cure mechanisms were also studied in a temperature-frequency dependent Dielectric Spectroscopy.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"159 ","pages":"Article 103621"},"PeriodicalIF":4.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691401","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 : 2025-12-01DOI: 10.1016/j.ndteint.2025.103620
Cristian A. Calistru , Ehsan Mohseni , Vedran Tunukovic , S. Gareth Pierce , David Lines , Charles N. MacLeod , Randika K.W. Vithanage , Iain Bomphray , Tobias Weis , Gavin Munro , Tom O'Hare
Resin infusion paired with Out of Autoclave (OoA) curing offers an alternative to infrastructure-heavy autoclave-based manufacturing. However, lower fibre volume fractions and increased porosity from uneven resin flow limit the adoption of OoA processes in safety-critical applications. Consequently, there is demand for in-situ monitoring tools to track resin progression and ensure full permeation. Prior methods, including optical fibres and electromagnetic sensors, can infer front position but are intrusive or hard to scale. This research investigates leaky Lamb waves generated by ultrasonic transducers embedded in the top lid of an infusion mould. To isolate wave-fluid interactions, liquid-only measurements in a 2.0 mm thick infusion box are collected, removing laminate heterogeneity and enabling acquisition of controllable consecutive measurements, enabling the development and validation of predictive models under well-defined conditions. Attenuation of the fundamental antisymmetric mode (A0) as resin reaches the sensing region was demonstrated through theoretical and simulation-based analysis, highlighting the potential of Ultrasonic Guided Waves (UGW) for real-time fluid tracking. A custom experimental setup enabled consistent repeatable measurements of an advancing liquid front. A parametric study investigated the effects of geometry and fluid on signal amplitude, determining sensor spacing for sensitivity and areal coverage. Ultrasonic measurements were correlated with time-stamped images of the resin front through a machine-vision algorithm. Several functional approximation methods were applied to estimate liquid position from ultrasonic data, capturing the general trends in flow behaviour. The models yielded robust predictions, with mean errors of 5–7 % of the sensor spacing, despite environmental variations and system nonlinearities contributing to data variability.
{"title":"A step towards ultrasonic guided wave monitoring for resin infusion front position estimation in composites manufacturing","authors":"Cristian A. Calistru , Ehsan Mohseni , Vedran Tunukovic , S. Gareth Pierce , David Lines , Charles N. MacLeod , Randika K.W. Vithanage , Iain Bomphray , Tobias Weis , Gavin Munro , Tom O'Hare","doi":"10.1016/j.ndteint.2025.103620","DOIUrl":"10.1016/j.ndteint.2025.103620","url":null,"abstract":"<div><div>Resin infusion paired with Out of Autoclave (OoA) curing offers an alternative to infrastructure-heavy autoclave-based manufacturing. However, lower fibre volume fractions and increased porosity from uneven resin flow limit the adoption of OoA processes in safety-critical applications. Consequently, there is demand for in-situ monitoring tools to track resin progression and ensure full permeation. Prior methods, including optical fibres and electromagnetic sensors, can infer front position but are intrusive or hard to scale. This research investigates leaky Lamb waves generated by ultrasonic transducers embedded in the top lid of an infusion mould. To isolate wave-fluid interactions, liquid-only measurements in a 2.0 mm thick infusion box are collected, removing laminate heterogeneity and enabling acquisition of controllable consecutive measurements, enabling the development and validation of predictive models under well-defined conditions. Attenuation of the fundamental antisymmetric mode (A0) as resin reaches the sensing region was demonstrated through theoretical and simulation-based analysis, highlighting the potential of Ultrasonic Guided Waves (UGW) for real-time fluid tracking. A custom experimental setup enabled consistent repeatable measurements of an advancing liquid front. A parametric study investigated the effects of geometry and fluid on signal amplitude, determining sensor spacing for sensitivity and areal coverage. Ultrasonic measurements were correlated with time-stamped images of the resin front through a machine-vision algorithm. Several functional approximation methods were applied to estimate liquid position from ultrasonic data, capturing the general trends in flow behaviour. The models yielded robust predictions, with mean errors of 5–7 % of the sensor spacing, despite environmental variations and system nonlinearities contributing to data variability.</div></div>","PeriodicalId":18868,"journal":{"name":"Ndt & E International","volume":"159 ","pages":"Article 103620"},"PeriodicalIF":4.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145691403","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 : 2025-12-01DOI: 10.1016/j.ndteint.2025.103618
Yigang Cheng , Wenze Shi , Chao Lu , Weiwei Chen , Yujia Zeng , Bo Hu
High-temperature alloy bolts used in aerospace engines face some issues, such as high ultrasonic attenuation coefficient and low electrical conductivity compared to traditional metal materials. Common measurement methods encounter problems, including the impact of piezoelectric ultrasonic coupling agents on acoustic time accuracy, film easy shedding of permanent mounted transducer system (PMTS), and low SNR in EMAT measurements. To date, there are limited high-precision ultrasonic measurement technologies available for the preload of bolt fasteners in high-temperature alloy materials such as GH4169. This research introduces a technique for measuring the time of flight (TOF) of ultrasonic waves within bolts using Laser-electromagnetic acoustic transducer (Laser-EMAT) technology and determines the preload of bolts employing either the mono-wave method or the bi-wave method. Utilizing numerical simulation and experimental validation, the study analyses the ultrasonic wave modes and their SNR under three laser-induced mechanisms: thermoelastic, ablation, and surface constraint, in GH4169 bolts. We establish a linear relationship between acoustic TOF and bolt preload and compare the measurement accuracy of the mono- and bi-wave methods under these three laser-induced mechanisms. The research showed that: Under the thermoelastic mechanism, the average relative errors of the mono-wave method and bi-wave method in measuring 10 kN and above loads were lower than 4.2 %, 4.9 %, respectively. Although the ablation mechanism can improve the SNR of longitudinal waves compared with the thermoelastic mechanism, the measurement accuracy decreases. Using the surface constraint mechanism with silver-grease as the coating material, the SNR of longitudinal waves was improved by 13 dB compared with the thermoelastic mechanism. The mono-wave method with second longitudinal waves achieved higher accuracy than the first longitudinal wave approach, showing under 1.6 % average error at loads of 5 kN and above. This study offers a novel high-precision testing approach for measuring the preload in aerospace engine high-temperature alloy bolts with a high level of ultrasonic wave attenuation.
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