Due to the presence of various corrosive chemicals in LPG (liquefied petroleum gas, or propane) storage tanks, it is very likely to cause different degrees of corrosion in the tank and derive various defects. This article analyzes the main characteristics and types of defects found in storage tanks and provides an overview of ultrasonic testing and monitoring of defects such as hydrogen blistering and hydrogen-induced cracking.
{"title":"Ultrasonic testing and Monitoring of Hydrogen blistering and Hydrogen-induced Cracking of LPG Storage Tanks","authors":"Lixiang Hong, Fu Yang, Dongyao Chen, Minghui Sun","doi":"10.32548/2024.me-04394","DOIUrl":"https://doi.org/10.32548/2024.me-04394","url":null,"abstract":"Due to the presence of various corrosive chemicals in LPG (liquefied petroleum gas, or propane) storage tanks, it is very likely to cause different degrees of corrosion in the tank and derive various defects. This article analyzes the main characteristics and types of defects found in storage tanks and provides an overview of ultrasonic testing and monitoring of defects such as hydrogen blistering and hydrogen-induced cracking.","PeriodicalId":505083,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139878088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, self-healing of mortar was achieved by “built-in” carbonation of soluble Na2CO3 and Ca(OH)2. The effect of carbonate and calcium ions, available either internally or externally by conditioning the specimens with Ca(OH)2 and Na2CO3 solution, on the formation of calcite in cracks was investigated. The acoustic events were monitored and compared in the loading process before and after healing. Furthermore, a calibration test was carried out to distinguish the characteristic acoustic emission events of the fracture of the matrix and of healing products. It was found that the distribution of acoustic energy with FMA (frequency at maximum amplitude) and the hits with duration show a consistent trend with that of calibration. The change of tensile to shear cracking ratio in reloading illustrates a self-healing effect of cracks. Meanwhile, X-ray diffraction analysis indicates more calcite formed in the crack of self-healing specimens. The pretreated ceramsite-containing specimens exhibit the predominate self-healing effect due to the internally available CO32– and sufficient Ca2+ as compared to the others.
{"title":"Acoustic Emission Waveform Characterization of Crack Origin In Self-Healing of Mortar Due to Internal Carbonation","authors":"Wenting Li, Shan Qiang, Qi Wei","doi":"10.32548/2024.me-04343","DOIUrl":"https://doi.org/10.32548/2024.me-04343","url":null,"abstract":"In this study, self-healing of mortar was achieved by “built-in” carbonation of soluble Na2CO3 and Ca(OH)2. The effect of carbonate and calcium ions, available either internally or externally by conditioning the specimens with Ca(OH)2 and Na2CO3 solution, on the formation of calcite in cracks was investigated. The acoustic events were monitored and compared in the loading process before and after healing. Furthermore, a calibration test was carried out to distinguish the characteristic acoustic emission events of the fracture of the matrix and of healing products. It was found that the distribution of acoustic energy with FMA (frequency at maximum amplitude) and the hits with duration show a consistent trend with that of calibration. The change of tensile to shear cracking ratio in reloading illustrates a self-healing effect of cracks. Meanwhile, X-ray diffraction analysis indicates more calcite formed in the crack of self-healing specimens. The pretreated ceramsite-containing specimens exhibit the predominate self-healing effect due to the internally available CO32– and sufficient Ca2+ as compared to the others.","PeriodicalId":505083,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139873096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, self-healing of mortar was achieved by “built-in” carbonation of soluble Na2CO3 and Ca(OH)2. The effect of carbonate and calcium ions, available either internally or externally by conditioning the specimens with Ca(OH)2 and Na2CO3 solution, on the formation of calcite in cracks was investigated. The acoustic events were monitored and compared in the loading process before and after healing. Furthermore, a calibration test was carried out to distinguish the characteristic acoustic emission events of the fracture of the matrix and of healing products. It was found that the distribution of acoustic energy with FMA (frequency at maximum amplitude) and the hits with duration show a consistent trend with that of calibration. The change of tensile to shear cracking ratio in reloading illustrates a self-healing effect of cracks. Meanwhile, X-ray diffraction analysis indicates more calcite formed in the crack of self-healing specimens. The pretreated ceramsite-containing specimens exhibit the predominate self-healing effect due to the internally available CO32– and sufficient Ca2+ as compared to the others.
{"title":"Acoustic Emission Waveform Characterization of Crack Origin In Self-Healing of Mortar Due to Internal Carbonation","authors":"Wenting Li, Shan Qiang, Qi Wei","doi":"10.32548/2024.me-04343","DOIUrl":"https://doi.org/10.32548/2024.me-04343","url":null,"abstract":"In this study, self-healing of mortar was achieved by “built-in” carbonation of soluble Na2CO3 and Ca(OH)2. The effect of carbonate and calcium ions, available either internally or externally by conditioning the specimens with Ca(OH)2 and Na2CO3 solution, on the formation of calcite in cracks was investigated. The acoustic events were monitored and compared in the loading process before and after healing. Furthermore, a calibration test was carried out to distinguish the characteristic acoustic emission events of the fracture of the matrix and of healing products. It was found that the distribution of acoustic energy with FMA (frequency at maximum amplitude) and the hits with duration show a consistent trend with that of calibration. The change of tensile to shear cracking ratio in reloading illustrates a self-healing effect of cracks. Meanwhile, X-ray diffraction analysis indicates more calcite formed in the crack of self-healing specimens. The pretreated ceramsite-containing specimens exhibit the predominate self-healing effect due to the internally available CO32– and sufficient Ca2+ as compared to the others.","PeriodicalId":505083,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139813275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jie Wang, Teng Zheng, Dongxue Han, Liang Peng, Tianying Chang, Honghai Cui, Jin Zhang
Glass fiber composites are widely used due to their unique performance advantages. However, defects in glass fiber composites can significantly affect their performance, making nondestructive evaluation necessary. During the X-ray spectral imaging of glass fiber composites, the 0/90° cross-stacking mode of glass fiber cloth results in irregular horizontal and vertical stripe noise, which seriously reduces the clarity of defect detection. Therefore, an appropriate algorithm is required to remove the noise. In this study, by analyzing the Fourier spectrum of X-ray spectral images of glass fiber composites, it was found that the stripe information is concealed in the vertical and horizontal bright lines in the middle of the Fourier spectrum image. A novel cross-sector filter was designed, and a stripe noise removal algorithm based on the cross-sector filter was proposed. The degree of the filter’s central angle can be adjusted according to the distribution of the stripe noise in the frequency domain, which removes the noise without losing much useful image information.
玻璃纤维复合材料因其独特的性能优势而被广泛使用。然而，玻璃纤维复合材料中的缺陷会严重影响其性能，因此有必要对其进行无损评估。在对玻璃纤维复合材料进行 X 射线光谱成像时，玻璃纤维布的 0/90° 交叉堆叠模式会产生不规则的水平和垂直条纹噪声，严重降低缺陷检测的清晰度。因此，需要一种合适的算法来去除噪声。本研究通过分析玻璃纤维复合材料 X 射线光谱图像的傅立叶光谱，发现条纹信息隐藏在傅立叶光谱图像中间的垂直和水平亮线中。研究人员设计了一种新型交叉扇形滤波器，并提出了一种基于交叉扇形滤波器的条纹噪声去除算法。滤波器中心角的度数可根据条纹噪声在频域中的分布进行调整，从而在去除噪声的同时不会丢失太多有用的图像信息。
{"title":"Investigation on the elimination of striations in NDE of glass fiber composites","authors":"Jie Wang, Teng Zheng, Dongxue Han, Liang Peng, Tianying Chang, Honghai Cui, Jin Zhang","doi":"10.32548/2024.me-04347","DOIUrl":"https://doi.org/10.32548/2024.me-04347","url":null,"abstract":"Glass fiber composites are widely used due to their unique performance advantages. However, defects in glass fiber composites can significantly affect their performance, making nondestructive evaluation necessary. During the X-ray spectral imaging of glass fiber composites, the 0/90° cross-stacking mode of glass fiber cloth results in irregular horizontal and vertical stripe noise, which seriously reduces the clarity of defect detection. Therefore, an appropriate algorithm is required to remove the noise. In this study, by analyzing the Fourier spectrum of X-ray spectral images of glass fiber composites, it was found that the stripe information is concealed in the vertical and horizontal bright lines in the middle of the Fourier spectrum image. A novel cross-sector filter was designed, and a stripe noise removal algorithm based on the cross-sector filter was proposed. The degree of the filter’s central angle can be adjusted according to the distribution of the stripe noise in the frequency domain, which removes the noise without losing much useful image information.","PeriodicalId":505083,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139887367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the presence of various corrosive chemicals in LPG (liquefied petroleum gas, or propane) storage tanks, it is very likely to cause different degrees of corrosion in the tank and derive various defects. This article analyzes the main characteristics and types of defects found in storage tanks and provides an overview of ultrasonic testing and monitoring of defects such as hydrogen blistering and hydrogen-induced cracking.
{"title":"Ultrasonic testing and Monitoring of Hydrogen blistering and Hydrogen-induced Cracking of LPG Storage Tanks","authors":"Lixiang Hong, Fu Yang, Dongyao Chen, Minghui Sun","doi":"10.32548/2024.me-04394","DOIUrl":"https://doi.org/10.32548/2024.me-04394","url":null,"abstract":"Due to the presence of various corrosive chemicals in LPG (liquefied petroleum gas, or propane) storage tanks, it is very likely to cause different degrees of corrosion in the tank and derive various defects. This article analyzes the main characteristics and types of defects found in storage tanks and provides an overview of ultrasonic testing and monitoring of defects such as hydrogen blistering and hydrogen-induced cracking.","PeriodicalId":505083,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139818015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jie Wang, Teng Zheng, Dongxue Han, Liang Peng, Tianying Chang, Honghai Cui, Jin Zhang
Glass fiber composites are widely used due to their unique performance advantages. However, defects in glass fiber composites can significantly affect their performance, making nondestructive evaluation necessary. During the X-ray spectral imaging of glass fiber composites, the 0/90° cross-stacking mode of glass fiber cloth results in irregular horizontal and vertical stripe noise, which seriously reduces the clarity of defect detection. Therefore, an appropriate algorithm is required to remove the noise. In this study, by analyzing the Fourier spectrum of X-ray spectral images of glass fiber composites, it was found that the stripe information is concealed in the vertical and horizontal bright lines in the middle of the Fourier spectrum image. A novel cross-sector filter was designed, and a stripe noise removal algorithm based on the cross-sector filter was proposed. The degree of the filter’s central angle can be adjusted according to the distribution of the stripe noise in the frequency domain, which removes the noise without losing much useful image information.
玻璃纤维复合材料因其独特的性能优势而被广泛使用。然而，玻璃纤维复合材料中的缺陷会严重影响其性能，因此有必要对其进行无损评估。在对玻璃纤维复合材料进行 X 射线光谱成像时，玻璃纤维布的 0/90° 交叉堆叠模式会产生不规则的水平和垂直条纹噪声，严重降低缺陷检测的清晰度。因此，需要一种合适的算法来去除噪声。本研究通过分析玻璃纤维复合材料 X 射线光谱图像的傅立叶光谱，发现条纹信息隐藏在傅立叶光谱图像中间的垂直和水平亮线中。研究人员设计了一种新型交叉扇形滤波器，并提出了一种基于交叉扇形滤波器的条纹噪声去除算法。滤波器中心角的度数可根据条纹噪声在频域中的分布进行调整，从而在去除噪声的同时不会丢失太多有用的图像信息。
{"title":"Investigation on the elimination of striations in NDE of glass fiber composites","authors":"Jie Wang, Teng Zheng, Dongxue Han, Liang Peng, Tianying Chang, Honghai Cui, Jin Zhang","doi":"10.32548/2024.me-04347","DOIUrl":"https://doi.org/10.32548/2024.me-04347","url":null,"abstract":"Glass fiber composites are widely used due to their unique performance advantages. However, defects in glass fiber composites can significantly affect their performance, making nondestructive evaluation necessary. During the X-ray spectral imaging of glass fiber composites, the 0/90° cross-stacking mode of glass fiber cloth results in irregular horizontal and vertical stripe noise, which seriously reduces the clarity of defect detection. Therefore, an appropriate algorithm is required to remove the noise. In this study, by analyzing the Fourier spectrum of X-ray spectral images of glass fiber composites, it was found that the stripe information is concealed in the vertical and horizontal bright lines in the middle of the Fourier spectrum image. A novel cross-sector filter was designed, and a stripe noise removal algorithm based on the cross-sector filter was proposed. The degree of the filter’s central angle can be adjusted according to the distribution of the stripe noise in the frequency domain, which removes the noise without losing much useful image information.","PeriodicalId":505083,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139827154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to cyclic mechanical loading, railcar wheels are subject to the development of internal fatigue cracks in the rim underneath the tread surface. Off-line inspections are extremely laborious and require extended out-of-service time, and most existing in-line inspection systems that use conventional ultrasonics or electromagnetic acoustic transducer (EMAT) techniques have several drawbacks that limit their full-scale deployment in service. This paper discusses the work performed on the initial research and development of a proof-of-concept novel magnetostrictive EMAT sensor for in-motion railcar wheel inspection. Wheelsets with known internal discontinuities and a 3.7 m long panelized track were used to demonstrate the feasibility of the developed approach and methods. The results obtained from these tests have shown that the magnetostrictive EMAT sensor that generates 5 mm wavelength shear horizontal waves detects both surface defects and internal fatigue cracks with an excellent signal-to-noise ratio. Different wavelengths can also be added to the sensors to enhance or complement the detection of fatigue cracks at different depths. A total of four or five sensors located at standard concrete crosstie spacing along each rail would be able to provide complete coverage on wheels ranging from 711 to 965 mm in diameter with ±90° wheel coverage per sensor, and a theoretical inspection speed of 56 kph can be achieved using this approach.
{"title":"In-Motion Railcar Wheel Inspection using Magnetostrictive EMATs","authors":"Anish Poudel, Borja Lopez, Syed Ali, Josh Bensur","doi":"10.32548/2024.me-04376","DOIUrl":"https://doi.org/10.32548/2024.me-04376","url":null,"abstract":"Due to cyclic mechanical loading, railcar wheels are subject to the development of internal fatigue cracks in the rim underneath the tread surface. Off-line inspections are extremely laborious and require extended out-of-service time, and most existing in-line inspection systems that use conventional ultrasonics or electromagnetic acoustic transducer (EMAT) techniques have several drawbacks that limit their full-scale deployment in service. This paper discusses the work performed on the initial research and development of a proof-of-concept novel magnetostrictive EMAT sensor for in-motion railcar wheel inspection. Wheelsets with known internal discontinuities and a 3.7 m long panelized track were used to demonstrate the feasibility of the developed approach and methods. The results obtained from these tests have shown that the magnetostrictive EMAT sensor that generates 5 mm wavelength shear horizontal waves detects both surface defects and internal fatigue cracks with an excellent signal-to-noise ratio. Different wavelengths can also be added to the sensors to enhance or complement the detection of fatigue cracks at different depths. A total of four or five sensors located at standard concrete crosstie spacing along each rail would be able to provide complete coverage on wheels ranging from 711 to 965 mm in diameter with ±90° wheel coverage per sensor, and a theoretical inspection speed of 56 kph can be achieved using this approach.","PeriodicalId":505083,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139639855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents an experimental prototype developed for rail flaw imaging. This capability can help obtain quantitative information on detected flaws during manual flaw verification. Ultrasonic synthetic aperture focus (SAF) imaging has advantages over phased-array imaging for both speed and accuracy. The prototype developed is hosted in a portable and battery-powered carry-on size case. The probe is a linear ultrasonic array mounted on a wedge and with a position encoder to build 3D point clouds from 2D beamformed images. The prototype includes several advances over the basic SAF technique, including sparse subarray firing that allows fast imaging speeds (e.g., 25 Hz) without sacrificing image accuracy. Validation results are presented from scans performed on rail sections from the FRA rail defect library, which contains natural transverse defects and artificial end-drilled hole defects. The tests showed good accuracy in defect size and shape, as compared to the available ground truth information, for defects located away from the railhead corners. Additional developments are required to properly cover the head corners, and especially in the case of heavily worn rails.
本文介绍了为钢轨缺陷成像开发的实验原型。这种功能有助于在人工缺陷验证过程中获得检测到的缺陷的定量信息。与相控阵成像相比，超声波合成孔径聚焦（SAF）成像在速度和精度方面都具有优势。开发的原型机装在一个便携式电池供电的手提箱中。探头是一个安装在楔形物体上的线性超声阵列，带有一个位置编码器，可从二维波束成形图像中建立三维点云。该原型与基本的 SAF 技术相比有多项进步，包括稀疏子阵列点火，可在不影响图像精度的情况下实现快速成像（例如 25 Hz）。验证结果来自对 FRA 轨道缺陷库中的轨道断面进行的扫描，该缺陷库包含自然横向缺陷和人工端面钻孔缺陷。测试表明，与现有的地面实况信息相比，位于远离轨头拐角处的缺陷在尺寸和形状上具有良好的准确性。还需要进一步开发，以适当覆盖轨头拐角，特别是磨损严重的钢轨。
{"title":"Rail Flaw Imaging Prototype Based on Improved Ultrasonic Synthetic Aperture Focus Method","authors":"Chengyang Huang, F. Lanza di Scalea","doi":"10.32548/2024.me-04371","DOIUrl":"https://doi.org/10.32548/2024.me-04371","url":null,"abstract":"This paper presents an experimental prototype developed for rail flaw imaging. This capability can help obtain quantitative information on detected flaws during manual flaw verification. Ultrasonic synthetic aperture focus (SAF) imaging has advantages over phased-array imaging for both speed and accuracy. The prototype developed is hosted in a portable and battery-powered carry-on size case. The probe is a linear ultrasonic array mounted on a wedge and with a position encoder to build 3D point clouds from 2D beamformed images. The prototype includes several advances over the basic SAF technique, including sparse subarray firing that allows fast imaging speeds (e.g., 25 Hz) without sacrificing image accuracy. Validation results are presented from scans performed on rail sections from the FRA rail defect library, which contains natural transverse defects and artificial end-drilled hole defects. The tests showed good accuracy in defect size and shape, as compared to the available ground truth information, for defects located away from the railhead corners. Additional developments are required to properly cover the head corners, and especially in the case of heavily worn rails.","PeriodicalId":505083,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139638240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper discusses the development of an in situ noncontact electromagnetic acoustic transducer (EMAT) nondestructive evaluation technology to determine rail neutral temperature and estimate rail stress in continuous welded rail (CWR). Stresses develop in CWR due to a lack of expansion joints to accommodate thermal expansion and contraction of the rail when ambient temperatures vary over time. The novelty of the work presented is the usage of ultrasonic birefringence properties using EMATs to estimate thermally induced stresses in rails. EMATs produce polarized shear waves propagating through the rail web in the pulse-echo mode. Experimental tests were performed on machined 136RE and 141RE rail material with applied compressive and tensile stresses to explore the stress-birefringence behavior. Two additional sets of experimental tests were conducted on full-size rail sections with in situ surface conditions to study variations in the in situ birefringence and the acoustic stress constant in different rail materials including 115RE rail, 119RE rail, two different 136RE rails, and 141RE rail. The results show a highly linear relationship between the stresses applied and the measured acoustic birefringence.
{"title":"Birefringence Technique for Evaluating Thermal Stresses in Railroad Rails","authors":"Aqeel Fadhil, Glenn Washer, Anish Poudel","doi":"10.32548/2024.me-04382","DOIUrl":"https://doi.org/10.32548/2024.me-04382","url":null,"abstract":"This paper discusses the development of an in situ noncontact electromagnetic acoustic transducer (EMAT) nondestructive evaluation technology to determine rail neutral temperature and estimate rail stress in continuous welded rail (CWR). Stresses develop in CWR due to a lack of expansion joints to accommodate thermal expansion and contraction of the rail when ambient temperatures vary over time. The novelty of the work presented is the usage of ultrasonic birefringence properties using EMATs to estimate thermally induced stresses in rails. EMATs produce polarized shear waves propagating through the rail web in the pulse-echo mode. Experimental tests were performed on machined 136RE and 141RE rail material with applied compressive and tensile stresses to explore the stress-birefringence behavior. Two additional sets of experimental tests were conducted on full-size rail sections with in situ surface conditions to study variations in the in situ birefringence and the acoustic stress constant in different rail materials including 115RE rail, 119RE rail, two different 136RE rails, and 141RE rail. The results show a highly linear relationship between the stresses applied and the measured acoustic birefringence.","PeriodicalId":505083,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139635881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the latest findings of a nondestructive evaluation technique currently under development at the University of Pittsburgh to determine the rail neutral temperature (RNT) in continuous welded rails. The technique is based on the extraction of relevant features from rail vibrations and the use of machine learning (ML) to associate these features to the longitudinal stress of the rail of interest. The features contain the spectral information of the vibrations and are pooled together by frequency domain decomposition for input to ML algorithms. Minimum redundancy–maximum relevance and neighboring component analysis are used to identify relevant features to reduce the size of the input vector. In addition, seven algorithms were considered to identify the most accurate model for neutral temperature with respect to the ground truth RNT measured with a strain-gage rosette. The data used in this study were collected from a 5° curved rail on concrete ties. The vibrations were triggered with a hammer and recorded with a few wireless and wired accelerometers attached on the railhead. The results showed that the Gaussian process regressor performs best, and as few as 20 frequencies can be used to predict the RNT with sufficient accuracy.
{"title":"Nondestructive Estimation of Neutral Temperature in Rails: A Comparative Study of Machine Learning Strategies","authors":"Matthew Belding, A. Enshaeian, Piervincenzo Rizzo","doi":"10.32548/2024.me-04384","DOIUrl":"https://doi.org/10.32548/2024.me-04384","url":null,"abstract":"This paper presents the latest findings of a nondestructive evaluation technique currently under development at the University of Pittsburgh to determine the rail neutral temperature (RNT) in continuous welded rails. The technique is based on the extraction of relevant features from rail vibrations and the use of machine learning (ML) to associate these features to the longitudinal stress of the rail of interest. The features contain the spectral information of the vibrations and are pooled together by frequency domain decomposition for input to ML algorithms. Minimum redundancy–maximum relevance and neighboring component analysis are used to identify relevant features to reduce the size of the input vector. In addition, seven algorithms were considered to identify the most accurate model for neutral temperature with respect to the ground truth RNT measured with a strain-gage rosette. The data used in this study were collected from a 5° curved rail on concrete ties. The vibrations were triggered with a hammer and recorded with a few wireless and wired accelerometers attached on the railhead. The results showed that the Gaussian process regressor performs best, and as few as 20 frequencies can be used to predict the RNT with sufficient accuracy.","PeriodicalId":505083,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139634310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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