Jessy Nemati, Alexander Clark, Ian Gatley, John Federici, Alan Fletcher
This paper showcases terahertz nondestructive detection of corrosion buried underneath a multilayer paint stack. Periodically, during the accelerated corrosion protocol, samples are removed from the environmental chambers and characterized using terahertz pulse imaging. Analysis of the reflected waveforms indicates that corrosion leads to a decrease in the amplitude of the deconvoluted pulse, which reflects from the metallic layer. The decrease in amplitude results from a roughening of the metallic surface with corrosion. Surface roughness increases with corrosion, eventually leading to detachment of the multilayer paint stack from the substrate.
{"title":"Terahertz Nondestructive Evaluation of Corroding Multilayer Paint Stacks","authors":"Jessy Nemati, Alexander Clark, Ian Gatley, John Federici, Alan Fletcher","doi":"10.32548/2024.me-04360","DOIUrl":"https://doi.org/10.32548/2024.me-04360","url":null,"abstract":"This paper showcases terahertz nondestructive detection of corrosion buried underneath a multilayer paint stack. Periodically, during the accelerated corrosion protocol, samples are removed from the environmental chambers and characterized using terahertz pulse imaging. Analysis of the reflected waveforms indicates that corrosion leads to a decrease in the amplitude of the deconvoluted pulse, which reflects from the metallic layer. The decrease in amplitude results from a roughening of the metallic surface with corrosion. Surface roughness increases with corrosion, eventually leading to detachment of the multilayer paint stack from the substrate.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141032924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the field of nondestructive testing (NDT), phased array ultrasonic testing (PAUT) stands out as a significant advancement, reshaping the way we inspect welds. In this article, we’ll explore the historical progression of weld inspection, from conventional ultrasonic testing (UT) to the rise of PAUT, and the technical aspects and advancements that have positioned PAUT as a game changer, particularly in industry standards set by organizations like the American Welding Society (AWS) and American Society of Mechanical Engineers (ASME). Our journey will include an examination of the core components of PAUT, such as the pulser/receiver, probe technology, and data analysis software. We’ll also delve into the practical applications of beamforming, sectorial and linear scanning, and various scan views used in weld inspection. As we discuss the advantages of PAUT over conventional UT and its integration into industry codes, you’ll gain insight into how this technology has become an essential tool for ensuring the integrity of welds in a range of applications.
{"title":"The Evolution of Weld Inspection: Unlocking the Potential of Phased Array Ultrasonic Testing","authors":"Will Haworth","doi":"10.32548/2024.me-04428","DOIUrl":"https://doi.org/10.32548/2024.me-04428","url":null,"abstract":"In the field of nondestructive testing (NDT), phased array ultrasonic testing (PAUT) stands out as a significant advancement, reshaping the way we inspect welds. In this article, we’ll explore the historical progression of weld inspection, from conventional ultrasonic testing (UT) to the rise of PAUT, and the technical aspects and advancements that have positioned PAUT as a game changer, particularly in industry standards set by organizations like the American Welding Society (AWS) and American Society of Mechanical Engineers (ASME).\u0000Our journey will include an examination of the core components of PAUT, such as the pulser/receiver, probe technology, and data analysis software. We’ll also delve into the practical applications of beamforming, sectorial and linear scanning, and various scan views used in weld inspection. As we discuss the advantages of PAUT over conventional UT and its integration into industry codes, you’ll gain insight into how this technology has become an essential tool for ensuring the integrity of welds in a range of applications.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141042513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Srivathasan S, Sanjoy Das, M. Ravindra, D. Mukherjee
Defect detectability studies are used in nondestructive testing to ascertain the reliability of the method of inspection. In digital radiography, with the growing prevalence of automation of quality control processes by image processing and machine learning, a threshold detection criterion based on quantifiable data from the digital radiograph could be explored. The use of the parameter contrast-to-noise ratio (CNR) of defect signal as a probability of detection (POD) threshold criterion is explored in this paper. A stainless steel block containing artificial defects of known dimensions and location is radiographed by a flat panel detector, and an empirical POD curve is constructed. Before the POD study, the edge response of the flat panel system is studied to ensure noninterference of adjacent defect signals, gain insights about the lateral spread of the defect signal, and provide information to choose the region of interest for CNR calculation. The effect of noise on the POD using CNR as the threshold criterion is also included in the present study. The use of CNR-based POD models for digital radiography to aid the comparison and development of automatic defect detection models is also discussed.
缺陷可探测性研究用于无损检测，以确定检测方法的可靠性。在数字射线摄影中，随着通过图像处理和机器学习实现质量控制流程自动化的日益普及，可以探索一种基于数字射线照片可量化数据的阈值检测标准。本文探讨了使用缺陷信号的对比度-噪声比（CNR）参数作为检测概率（POD）阈值标准。使用平板探测器对含有已知尺寸和位置的人造缺陷的不锈钢块进行射线照相，并构建经验 POD 曲线。在研究 POD 之前，先研究平板系统的边缘响应，以确保相邻缺陷信号互不干扰，深入了解缺陷信号的横向扩散情况，并为选择 CNR 计算的相关区域提供信息。本研究还包括噪声对使用 CNR 作为阈值标准的 POD 的影响。本研究还讨论了在数字射线摄影中使用基于 CNR 的 POD 模型来帮助比较和开发自动缺陷检测模型的问题。
{"title":"Edge Response and Defect Detectability in Flat Panel Digital Radiography","authors":"Srivathasan S, Sanjoy Das, M. Ravindra, D. Mukherjee","doi":"10.32548/2024.me-04372","DOIUrl":"https://doi.org/10.32548/2024.me-04372","url":null,"abstract":"Defect detectability studies are used in nondestructive testing to ascertain the reliability of the method of inspection. In digital radiography, with the growing prevalence of automation of quality control processes by image processing and machine learning, a threshold detection criterion based on quantifiable data from the digital radiograph could be explored. The use of the parameter contrast-to-noise ratio (CNR) of defect signal as a probability of detection (POD) threshold criterion is explored in this paper. A stainless steel block containing artificial defects of known dimensions and location is radiographed by a flat panel detector, and an empirical POD curve is constructed. Before the POD study, the edge response of the flat panel system is studied to ensure noninterference of adjacent defect signals, gain insights about the lateral spread of the defect signal, and provide information to choose the region of interest for CNR calculation. The effect of noise on the POD using CNR as the threshold criterion is also included in the present study. The use of CNR-based POD models for digital radiography to aid the comparison and development of automatic defect detection models is also discussed.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141040892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nondestructive evaluation using pulsed eddy current (PEC) has remarkable capabilities for the detection and characterization of hidden corrosion in multilayer structures. Previous works proposed maximum peak value, time-to-peak, and time-to-zero crossing of PEC signals for hidden corrosion detection. In practice, there are two important noise sources: probe liftoff and interlayer gap. These noise sources disable the aforementioned components in defect detection and classification. This paper delivers a new intelligent method for detection and classification of corrosion defects in two-layer structures at the presence of gap and liftoff. Application independent component analysis and principal component analysis to PEC signals for features extraction and Fisher’s linear discriminant method for classification provide an automatic material loss characterization in multilayer structures. Comparing the results with conventional methods based on PEC signals shows the importance of post-processing methods in the detection and quantification of corrosion.
{"title":"Intelligent Method for Corrosion Detection and Quantification in Aircraft Lap Joints Using Pulsed Eddy Current","authors":"M. Safizadeh, M. R. Malekan","doi":"10.32548/2024.me-04363","DOIUrl":"https://doi.org/10.32548/2024.me-04363","url":null,"abstract":"Nondestructive evaluation using pulsed eddy current (PEC) has remarkable capabilities for the detection and characterization of hidden corrosion in multilayer structures. Previous works proposed maximum peak value, time-to-peak, and time-to-zero crossing of PEC signals for hidden corrosion detection. In practice, there are two important noise sources: probe liftoff and interlayer gap. These noise sources disable the aforementioned components in defect detection and classification. This paper delivers a new intelligent method for detection and classification of corrosion defects in two-layer structures at the presence of gap and liftoff. Application independent component analysis and principal component analysis to PEC signals for features extraction and Fisher’s linear discriminant method for classification provide an automatic material loss characterization in multilayer structures. Comparing the results with conventional methods based on PEC signals shows the importance of post-processing methods in the detection and quantification of corrosion.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140756518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To assess the grain size of hybrid disks, we propose a simple network architecture—the wide-paralleled convolutional neural network (WP-CNN)—based solely on multibranch blocks and create a grain size classification model based on it. Multibranch blocks are used to enhance the capability of feature extraction, and the global average pooling layer was implemented to reduce the number of model parameters. To train and test the model, a dataset of ultrasonic scattering signals from a hybrid disk was constructed. The WP-CNN structure and hyperparameter selection were examined using the training set. The experiment demonstrated that, compared to traditional 1D convolutional neural network, 1D ResNet, and InceptionTime, the classification accuracy of this method can reach 92.3%. A comparison is made with the empirical mode decomposition scattering model and frequency spectra tree model. The proposed network provides accurate classification of grain size without physical parameters and specific physical models. The results show the deep learning method has the feasibility to evaluate hybrid disk grain size distribution.
{"title":"Multibranch Block-Based Grain Size Classification Of Hybrid Disk Using Ultrasonic Scattering: A Deep Learning Method","authors":"Xiao Liu, Zheng-xiao Sha, Jing Liang","doi":"10.32548/2024.me-04388","DOIUrl":"https://doi.org/10.32548/2024.me-04388","url":null,"abstract":"To assess the grain size of hybrid disks, we propose a simple network architecture—the wide-paralleled convolutional neural network (WP-CNN)—based solely on multibranch blocks and create a grain size classification model based on it. Multibranch blocks are used to enhance the capability of feature extraction, and the global average pooling layer was implemented to reduce the number of model parameters. To train and test the model, a dataset of ultrasonic scattering signals from a hybrid disk was constructed. The WP-CNN structure and hyperparameter selection were examined using the training set. The experiment demonstrated that, compared to traditional 1D convolutional neural network, 1D ResNet, and InceptionTime, the classification accuracy of this method can reach 92.3%. A comparison is made with the empirical mode decomposition scattering model and frequency spectra tree model. The proposed network provides accurate classification of grain size without physical parameters and specific physical models. The results show the deep learning method has the feasibility to evaluate hybrid disk grain size distribution.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140770352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This tutorial article briefly overviews the current state-of-the-art railcar axle inspection methods to detect and characterize axle discontinuities or indications. This paper also presents and discusses some of the initiatives conducted by MxV Rail (formerly TTCI) and other researchers on the use of emerging and advanced nondestructive evaluation (NDE) technologies that are at different phases of development and not commercially available. Finally, a brief discussion is provided on the need for novel in-motion axle inspection NDE methods for moving trains. Such technology would enhance the safety of railcar axles. The need depends on the regulations in a given jurisdiction and on the class of service (passenger, freight, certain regulated hazardous materials).
{"title":"Railcar Axle Inspection Current State, Future Needs, and Opportunities","authors":"Anish Poudel","doi":"10.32548/2024.me-04378","DOIUrl":"https://doi.org/10.32548/2024.me-04378","url":null,"abstract":"This tutorial article briefly overviews the current state-of-the-art railcar axle inspection methods to detect and characterize axle discontinuities or indications. This paper also presents and discusses some of the initiatives conducted by MxV Rail (formerly TTCI) and other researchers on the use of emerging and advanced nondestructive evaluation (NDE) technologies that are at different phases of development and not commercially available. Finally, a brief discussion is provided on the need for novel in-motion axle inspection NDE methods for moving trains. Such technology would enhance the safety of railcar axles. The need depends on the regulations in a given jurisdiction and on the class of service (passenger, freight, certain regulated hazardous materials).","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139537544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Continuously welded rails are connected without stress relief joints and, thus, thermally induced rail movement is constrained, which can result in the development of excessive axial stress and risk of rail failure. Nondestructive testing (NDT) methods that estimate in-place rail stress state or rail neutral temperature are desired. Some methods have been developed, but none satisfy the requirements for ideal monitoring in practice. We propose an NDT technique based on impulse-generated vibration, seeking high-frequency rail vibration resonances whose frequency maintains a consistent correlation with rail axial stress/strain across different temperatures, stress states, and rail support conditions. Rail temperature, axial strain, and vibration data were collected from an active Class 1 commercial rail line over a period of nearly two years. The frequencies of four consistent and clear resonance modes of the rail were monitored. One of the identified modes demonstrates a unique linear relation with axial strain across a range of temperatures and stress states at each of the two measurement locations. The developed linear relations were used to predict in-place strain and rail neutral temperature with acceptable accuracy across all the measurement data, although each test location exhibits a unique relation.
{"title":"Predicting Axial Stress State In Continuously Welded Rail Using Impulse-Generated Vibration Measurements","authors":"Chi-Luen Huang, John S Popovics","doi":"10.32548/2024.me-04377","DOIUrl":"https://doi.org/10.32548/2024.me-04377","url":null,"abstract":"Continuously welded rails are connected without stress relief joints and, thus, thermally induced rail movement is constrained, which can result in the development of excessive axial stress and risk of rail failure. Nondestructive testing (NDT) methods that estimate in-place rail stress state or rail neutral temperature are desired. Some methods have been developed, but none satisfy the requirements for ideal monitoring in practice. We propose an NDT technique based on impulse-generated vibration, seeking high-frequency rail vibration resonances whose frequency maintains a consistent correlation with rail axial stress/strain across different temperatures, stress states, and rail support conditions. Rail temperature, axial strain, and vibration data were collected from an active Class 1 commercial rail line over a period of nearly two years. The frequencies of four consistent and clear resonance modes of the rail were monitored. One of the identified modes demonstrates a unique linear relation with axial strain across a range of temperatures and stress states at each of the two measurement locations. The developed linear relations were used to predict in-place strain and rail neutral temperature with acceptable accuracy across all the measurement data, although each test location exhibits a unique relation.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139539865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A rapid helium mass spectrometry leak detection method is established to respond to problems of low sensitivity and efficiency in detecting leaks in large vessels. The optimized multistage tandem leak detection system improves leak detection sensitivity by increasing the amount of gas entering the analysis chamber. By involving the main pumping system in the detection process, the effective pumping speed is increased, resulting in a significant reduction in system response time. Additionally, the optimal leak detection vacuum required for maximizing the leak velocity indicating gas movement is determined, thereby further decreasing the system’s response time. Our application demonstrates that the optimized leak detection system increases sensitivity by one to two orders of magnitude, reduces system response time by over 90%, and shortens evacuation time by 7 h. Ultimately, the optimized design of the vacuum system developed for large vessels demonstrates greatly improved leak detection efficiency and overall capability.
{"title":"Optimization and testing of a Mass Spectrometer Leak Detection (MSLD) system","authors":"Guoyun Bai, Xindong Hu, X. Liao, Tao Chen, Rongmin Pan, Yanxia Li, Junlan Chang","doi":"10.32548/10.32548/2023.me-04345","DOIUrl":"https://doi.org/10.32548/10.32548/2023.me-04345","url":null,"abstract":"A rapid helium mass spectrometry leak detection method is established to respond to problems of low sensitivity and efficiency in detecting leaks in large vessels. The optimized multistage tandem leak detection system improves leak detection sensitivity by increasing the amount of gas entering the analysis chamber. By involving the main pumping system in the detection process, the effective pumping speed is increased, resulting in a significant reduction in system response time. Additionally, the optimal leak detection vacuum required for maximizing the leak velocity indicating gas movement is determined, thereby further decreasing the system’s response time. Our application demonstrates that the optimized leak detection system increases sensitivity by one to two orders of magnitude, reduces system response time by over 90%, and shortens evacuation time by 7 h. Ultimately, the optimized design of the vacuum system developed for large vessels demonstrates greatly improved leak detection efficiency and overall capability.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139013404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nondestructive testing of the adhesive bond properties of a bonded structure is essential in aviation, automotive, and other industries. In this study, a Lamb wave–based quantitative characterization method is proposed to determine the interfacial stiffness of bonded structures. A theoretical model is established, with which the dispersion relationship of Lamb waves in a bonded structure is investigated. Different interfacial states ranging from a perfect bond to a weak bond are simulated, and the numerical results show the sensitivity of Lamb waves to interfacial stiffness. A lateral excitation method is proposed to enhance the excitation of the interfacial sensitive Lamb wave modes, and laser ultrasonic experiments show the enhancement of the Lamb wave signals on aluminum-epoxy-aluminum samples generated by the lateral excitation method. Then, a rapid construction method of inversion objective function is presented to reconstruct the interfacial stiffness coefficient of a bonded structure, and its functionality is validated via finite element simulations. Finally, the interfacial properties of the samples are reconstructed using the inversion scheme.
{"title":"Inverse Determination Of Interfacial Properties of a Bonded Structure Using Lamb Waves Generated By Laser Lateral Excitation","authors":"Tianming Ye, Wenxiang Hu, Tao Chen, Yanxia Li","doi":"10.32548/2023.me-04319","DOIUrl":"https://doi.org/10.32548/2023.me-04319","url":null,"abstract":"Nondestructive testing of the adhesive bond properties of a bonded structure is essential in aviation, automotive, and other industries. In this study, a Lamb wave–based quantitative characterization method is proposed to determine the interfacial stiffness of bonded structures. A theoretical model is established, with which the dispersion relationship of Lamb waves in a bonded structure is investigated. Different interfacial states ranging from a perfect bond to a weak bond are simulated, and the numerical results show the sensitivity of Lamb waves to interfacial stiffness. A lateral excitation method is proposed to enhance the excitation of the interfacial sensitive Lamb wave modes, and laser ultrasonic experiments show the enhancement of the Lamb wave signals on aluminum-epoxy-aluminum samples generated by the lateral excitation method. Then, a rapid construction method of inversion objective function is presented to reconstruct the interfacial stiffness coefficient of a bonded structure, and its functionality is validated via finite element simulations. Finally, the interfacial properties of the samples are reconstructed using the inversion scheme.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138991734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Self-healing properties of super absorbent polymer (SAP) concrete can reduce the harmful effects of concrete cracking in structures. This study examines the self-healing process of mortars with different SAP content under dry and wet conditions through acoustic emission testing (AE) and elastic wave velocity testing. Findings indicate that the SAP mortar healing process has three stages: rapid water absorption, smooth water absorption, and drying. In a dry environment, increasing SAP content enhances AE activity, indicating internal crack self-healing via further hydration of unhydrated cement particles. In a wet environment, AE activity increases with increasing SAP content during the second healing cycle, indicating self-healing of the mortar matrix. These results suggest the use of SAP concrete could potentially mitigate future structural damage.
超强吸水聚合物（SAP）混凝土的自愈合特性可以减少结构中混凝土开裂的有害影响。本研究通过声发射测试（AE）和弹性波速测试，研究了不同 SAP 含量的砂浆在干湿条件下的自愈合过程。研究结果表明，SAP 砂浆的愈合过程分为三个阶段：快速吸水、平稳吸水和干燥。在干燥环境中，SAP 含量的增加会增强声发射活动，这表明内部裂缝会通过未水化水泥颗粒的进一步水化而自我愈合。在潮湿环境中，在第二个愈合周期中，随着 SAP 含量的增加，AE 活性也会增加，这表明砂浆基质具有自愈合能力。这些结果表明，使用 SAP 混凝土有可能减轻未来的结构损坏。
{"title":"Experimental Study On Acoustic Emission Characteristics of SAP Mortar Self-Healing Process","authors":"Nairan Wang, Yan Wang, Yihui Su, Haitao Zhao","doi":"10.32548/2023.me-04359","DOIUrl":"https://doi.org/10.32548/2023.me-04359","url":null,"abstract":"Self-healing properties of super absorbent polymer (SAP) concrete can reduce the harmful effects of concrete cracking in structures. This study examines the self-healing process of mortars with different SAP content under dry and wet conditions through acoustic emission testing (AE) and elastic wave velocity testing. Findings indicate that the SAP mortar healing process has three stages: rapid water absorption, smooth water absorption, and drying. In a dry environment, increasing SAP content enhances AE activity, indicating internal crack self-healing via further hydration of unhydrated cement particles. In a wet environment, AE activity increases with increasing SAP content during the second healing cycle, indicating self-healing of the mortar matrix. These results suggest the use of SAP concrete could potentially mitigate future structural damage.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139304191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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