The imaging range of the traditional total focusing method (TFM) is usually limited by the directivity of excitation of a single wave pattern. In this paper, a multiwave TFM technique is proposed, which uses both compression and shear vertical (SV) waves for detection and imaging simultaneously. Based on this technique, a special ultrasonic transducer for multiwave detection is designed that can balance the excitation amplitude of compression and SV waves. Multiwave TFM uses the compression and SV wave fields generated by the same excitation, and the signals reflected by the two sound fields passing through the discontinuity are received. The signals are respectively processed by TFM according to the compression and SV wave velocities. The two processed signals are shifted and aligned according to the time difference between the compression wave with SV wave propagation, and then added together. Finally, the detection image of the block is obtained. Through simulation and experiments, it is shown that the special transducer can optimize the imaging range and effect of multiwave TFM, and multiwave TFM can effectively detect discontinuities and reduce the rate of missed detection at higher steering angles. The detection results show that the maximum amplitude gain of multiwave TFM relative to TFM can be increased about 6 dB.
{"title":"Multiwave Total Focusing Method for Full-Matrix Imaging Using Ultrasonic Phased Array","authors":"Ping Zhang, Shou-guo Yan, Yu-xiang Dai, Juan Huang, Chao Kong, Fang-fang Shi, Bi-xing Zhang","doi":"10.32548/2021.me-04222","DOIUrl":"https://doi.org/10.32548/2021.me-04222","url":null,"abstract":"The imaging range of the traditional total focusing method (TFM) is usually limited by the directivity of excitation of a single wave pattern. In this paper, a multiwave TFM technique is proposed, which uses both compression and shear vertical (SV) waves for detection and imaging simultaneously. Based on this technique, a special ultrasonic transducer for multiwave detection is designed that can balance the excitation amplitude of compression and SV waves. Multiwave TFM uses the compression and SV wave fields generated by the same excitation, and the signals reflected by the two sound fields passing through the discontinuity are received. The signals are respectively processed by TFM according to the compression and SV wave velocities. The two processed signals are shifted and aligned according to the time difference between the compression wave with SV wave propagation, and then added together. Finally, the detection image of the block is obtained. Through simulation and experiments, it is shown that the special transducer can optimize the imaging range and effect of multiwave TFM, and multiwave TFM can effectively detect discontinuities and reduce the rate of missed detection at higher steering angles. The detection results show that the maximum amplitude gain of multiwave TFM relative to TFM can be increased about 6 dB.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49089460","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}
Within PAUT, inspectors have the option to apply various scanning techniques for performing weld inspections according to their configurations. These include the sectorial scan (S-scan) or a fixed-angle electronic scan (E-scan), or a combination of both called a compound S-scan. Compound S-scan, introduced around 2015 (Magruder 2016), has not been much explored, as not enough data can be extracted from the available resources to determine its effectiveness for inspection. Therefore, the author has taken a specific interest in studying this technique by comparing the available PAUT scanning techniques and providing options for selecting the most appropriate scanning techniques for the intended applications. For this purpose, a 25 mm thick welder qualification test plate with natural defects (verified by RT) was studied.
{"title":"Advantages of Compound S-scan over Sectorial Scan or E-scan: A Case Study","authors":"Stephen Sundarraj","doi":"10.32548/2021.me-04219","DOIUrl":"https://doi.org/10.32548/2021.me-04219","url":null,"abstract":"Within PAUT, inspectors have the option to apply various scanning techniques for performing weld inspections according to their configurations. These include the sectorial scan (S-scan) or a fixed-angle electronic scan (E-scan), or a combination of both called a compound S-scan. Compound S-scan, introduced around 2015 (Magruder 2016), has not been much explored, as not enough data can be extracted from the available resources to determine its effectiveness for inspection. Therefore, the author has taken a specific interest in studying this technique by comparing the available PAUT scanning techniques and providing options for selecting the most appropriate scanning techniques for the intended applications. For this purpose, a 25 mm thick welder qualification test plate with natural defects (verified by RT) was studied.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42007118","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}
Ultrasonic longitudinal wave propagation is studied in out-of-autoclave (OoA) carbon fiber–reinforced polymer composite material with varying levels of porosity contents. A combination of cure pressures and a solvent is used to produce specimens with void contents in the range of 0% to 22%. Ultrasonic measurements are made in through-transmission mode, and the data is processed to study various aspects of wave interaction with porosity in OoA specimens. The specimens with a wide range of void contents have enabled the study of broader trends of ultrasonic center frequency, wave velocity, and attenuation with respect to porosity. Results show ultrasonic center frequency and wave velocity are decreased linearly as the void content increases. The relationship of ultrasonic wave attenuation can be approximated by a logarithmic relationship when considering the full range of void content studied. Strength measurements of specimens with varying void contents are made using the flatwise tensile (FWT) test. It is observed that the strength rapidly decreases with increasing porosity. Correlations made between FWT strength, ultrasonic wave velocity, and attenuation are best described by logarithmic relationships. The data shows a potential for inferring strength knockdowns due to the presence of porosity based on ultrasonic measurements.
{"title":"Ultrasonic Evaluation of Porosity in Out-of-Autoclave Carbon Fiber–Reinforced Polymer Composite Material","authors":"D. Samaratunga, Joseph V. Severino, S. Kenderian","doi":"10.32548/2021.me-04198","DOIUrl":"https://doi.org/10.32548/2021.me-04198","url":null,"abstract":"Ultrasonic longitudinal wave propagation is studied in out-of-autoclave (OoA) carbon fiber–reinforced polymer composite material with varying levels of porosity contents. A combination of cure pressures and a solvent is used to produce specimens with void contents in the range of 0% to 22%. Ultrasonic measurements are made in through-transmission mode, and the data is processed to study various aspects of wave interaction with porosity in OoA specimens. The specimens with a wide range of void contents have enabled the study of broader trends of ultrasonic center frequency, wave velocity, and attenuation with respect to porosity. Results show ultrasonic center frequency and wave velocity are decreased linearly as the void content increases. The relationship of ultrasonic wave attenuation can be approximated by a logarithmic relationship when considering the full range of void content studied. Strength measurements of specimens with varying void contents are made using the flatwise tensile (FWT) test. It is observed that the strength rapidly decreases with increasing porosity. Correlations made between FWT strength, ultrasonic wave velocity, and attenuation are best described by logarithmic relationships. The data shows a potential for inferring strength knockdowns due to the presence of porosity based on ultrasonic measurements.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42749750","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}
Crack orientation, a critical parameter, significantly affects the dynamic properties of composite structures. Experimental free vibration tests were conducted on carbon fiber–reinforced polymer (CFRP) composite plates at room temperature with different crack orientations. Dynamic properties such as damping ratio, natural frequency, and storage modulus were measured using a four-channel dynamic pulse analyzer. Multi-sensors were mounted on the test plate to pick up the vibration signals. Experimental modal analysis was performed to identify the first three mode shapes of the defective plates. A numerical model using ANSYS software was developed via parametric investigation to predict the correlation between crack orientation and resonant frequencies with corresponding mode shapes. The orientation of the introduced cracks had a significant effect on the dynamic properties of CFRP composites. Vertical cracks had the most significant influence on the eigenvalues of the mode shape frequencies. Furthermore, the damping ratio was an effective method to detect the cracks in CFRP composites.
{"title":"Effect of Crack Orientation on Laminated CFRP Composites Using Vibration and Numerical Analysis","authors":"Essam B. Moustafa, K. Almitani, H. Hussein","doi":"10.32548/2021.me-04205","DOIUrl":"https://doi.org/10.32548/2021.me-04205","url":null,"abstract":"Crack orientation, a critical parameter, significantly affects the dynamic properties of composite structures. Experimental free vibration tests were conducted on carbon fiber–reinforced polymer (CFRP) composite plates at room temperature with different crack orientations. Dynamic properties such as damping ratio, natural frequency, and storage modulus were measured using a four-channel dynamic pulse analyzer. Multi-sensors were mounted on the test plate to pick up the vibration signals. Experimental modal analysis was performed to identify the first three mode shapes of the defective plates. A numerical model using ANSYS software was developed via parametric investigation to predict the correlation between crack orientation and resonant frequencies with corresponding mode shapes. The orientation of the introduced cracks had a significant effect on the dynamic properties of CFRP composites. Vertical cracks had the most significant influence on the eigenvalues of the mode shape frequencies. Furthermore, the damping ratio was an effective method to detect the cracks in CFRP composites.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44660544","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}
Development of a nondestructive evaluation (NDE) method to detect nascent hydrogen embrittlement (HE) in electroplated high-strength steel parts is becoming important for the aerospace industry. This research investigates the feasibility of surface acoustic waves (SAWs) measurements to distinguish between cadmium (Cd) plated SAE 4340 steel samples with low and high HE susceptibilities. SAWs were generated with a 10 MHz piezoelectric transducer and detected by line scans via a laser Doppler vibrometer setup. Using signal processing algorithms in MATLAB, SAW velocities as well as attenuation coefficients were estimated. Depth profiles of steel hardness near coatings were also evaluated using Vickers microindentation tests. Average steel hardness in not-baked samples was slightly increased. Cd coatings were characterized by laser and optical microscopy methods. Small variations found in thickness and surface roughness of the Cd coatings among the samples did not significantly affect the NDE results. On average, samples in the not-baked condition (high HE risk) exhibited lower SAW attenuation coefficients compared to immediately baked and late-baked conditions (low HE risk). However, it was not possible to distinguish between the manufacturing conditions of individual samples due to overlaps in attenuation measurement results. SAW velocities as estimated by the cross-correlation method were found to be not sensitive to manufacturing conditions.
{"title":"Nondestructive Evaluation of Electroplating-Induced Hydrogen Embrittlement in Cadmium-Coated High-Strength Steel Using Ultrasonic Surface Waves","authors":"H. Shahmiri, M. Viens","doi":"10.32548/2021.me-04231","DOIUrl":"https://doi.org/10.32548/2021.me-04231","url":null,"abstract":"Development of a nondestructive evaluation (NDE) method to detect nascent hydrogen embrittlement (HE) in electroplated high-strength steel parts is becoming important for the aerospace industry. This research investigates the feasibility of surface acoustic waves (SAWs) measurements to distinguish between cadmium (Cd) plated SAE 4340 steel samples with low and high HE susceptibilities. SAWs were generated with a 10 MHz piezoelectric transducer and detected by line scans via a laser Doppler vibrometer setup. Using signal processing algorithms in MATLAB, SAW velocities as well as attenuation coefficients were estimated. Depth profiles of steel hardness near coatings were also evaluated using Vickers microindentation tests. Average steel hardness in not-baked samples was slightly increased. Cd coatings were characterized by laser and optical microscopy methods. Small variations found in thickness and surface roughness of the Cd coatings among the samples did not significantly affect the NDE results. On average, samples in the not-baked condition (high HE risk) exhibited lower SAW attenuation coefficients compared to immediately baked and late-baked conditions (low HE risk). However, it was not possible to distinguish between the manufacturing conditions of individual samples due to overlaps in attenuation measurement results. SAW velocities as estimated by the cross-correlation method were found to be not sensitive to manufacturing conditions.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46370342","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}
V. Sukhorukov, D. Slesarev, I. Shpakov, V. Volokhovsky, A. Vorontsov, A. Shalashilin
The hazards and deterioration of operating wire ropes on overhead cranes, which articulate the ladle in the basic oxygen steelmaking process and are subjected to intensive periodic loads and exposure to high temperatures, are discussed. An automated condition monitoring system (ACMS) based on a magnetic flux leakage testing (MFL) flaw detector permanently installed on the rope under test is used. An algorithm of the rope’s residual tensile strength assessment is provided. A specially developed software that submits a decision on the rope’s condition to the crane operator is described. The practice of combining magnetic rope testing (MRT) and tensile strength analysis for the quantitative assessment of rope condition is reviewed. Practical issues are also discussed, such as how to establish the condition monitoring process, set loss thresholds for rope metallic cross-sectional area, and safely prolong the service life of rope.
{"title":"Automated Condition Monitoring with Remaining Lifetime Assessment for Wire Ropes in Ladle Cranes","authors":"V. Sukhorukov, D. Slesarev, I. Shpakov, V. Volokhovsky, A. Vorontsov, A. Shalashilin","doi":"10.32548/2021.me-04181","DOIUrl":"https://doi.org/10.32548/2021.me-04181","url":null,"abstract":"The hazards and deterioration of operating wire ropes on overhead cranes, which articulate the ladle in the basic oxygen steelmaking process and are subjected to intensive periodic loads and exposure to high temperatures, are discussed. An automated condition monitoring system (ACMS) based on a magnetic flux leakage testing (MFL) flaw detector permanently installed on the rope under test is used. An algorithm of the rope’s residual tensile strength assessment is provided. A specially developed software that submits a decision on the rope’s condition to the crane operator is described. The practice of combining magnetic rope testing (MRT) and tensile strength analysis for the quantitative assessment of rope condition is reviewed. Practical issues are also discussed, such as how to establish the condition monitoring process, set loss thresholds for rope metallic cross-sectional area, and safely prolong the service life of rope.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47269329","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}
Anne-Marie Allard, M. Grenier, Mitchell Sirois, C. Wassink
Eddy current testing (ECT) has been used for quite a while now and has been proven a reliable surface inspection technique for conductive materials. In the last 15 to 20 years, this technique has evolved toward the use of eddy current arrays (ECAs), and many applications can now benefit from this configuration to improve data quality, inspection speed, and ease of deployment, and considerably reduce operator dependency. The physics principle behind ECT and ECA is the same and was addressed in a previous issue of Materials Evaluation (Wassink et al. 2021). In this paper, we will discuss the main differences between ECT and ECA as well as how the arrangement of coils in an array can allow for optimized detection capabilities on different materials or types of defects. Common applications where ECA has demonstrated its strength will also be discussed.
{"title":"Understanding Eddy Current Array for High-Performance Inspections","authors":"Anne-Marie Allard, M. Grenier, Mitchell Sirois, C. Wassink","doi":"10.32548/2021.me-04226","DOIUrl":"https://doi.org/10.32548/2021.me-04226","url":null,"abstract":"Eddy current testing (ECT) has been used for quite a while now and has been proven a reliable surface inspection technique for conductive materials. In the last 15 to 20 years, this technique has evolved toward the use of eddy current arrays (ECAs), and many applications can now benefit from this configuration to improve data quality, inspection speed, and ease of deployment, and considerably reduce operator dependency. The physics principle behind ECT and ECA is the same and was addressed in a previous issue of Materials Evaluation (Wassink et al. 2021). In this paper, we will discuss the main differences between ECT and ECA as well as how the arrangement of coils in an array can allow for optimized detection capabilities on different materials or types of defects. Common applications where ECA has demonstrated its strength will also be discussed.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46710663","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}
Pub Date : 2021-10-01DOI: 10.32548/10.32548/2021.me-04233
H. Jalali, Yuhui Zeng, P. Rizzo, A. Bunger
This paper delves into the use of highly nonlinear solitary waves for the nondestructive identification and characterization of anisotropy in rocks. The nondestructive testing approach proposed expands upon a technique developed recently by some of the authors for the nondestructive characterization of engineering materials and structures. The technique uses the characteristics of solitary waves propagating in a periodic array of spherical particles in contact with the rock to be characterized. The features of the waves that bounce off the chain rock interface are used to infer some properties of the geomaterial under consideration. Numerical models and experimental validation were conducted to explore the feasibility of the method and to standardize the methodology for future widespread applications.
{"title":"Highly Nonlinear Solitary Waves to Estimate Orientation and Degree of Anisotropy in Rocks","authors":"H. Jalali, Yuhui Zeng, P. Rizzo, A. Bunger","doi":"10.32548/10.32548/2021.me-04233","DOIUrl":"https://doi.org/10.32548/10.32548/2021.me-04233","url":null,"abstract":"This paper delves into the use of highly nonlinear solitary waves for the nondestructive identification and characterization of anisotropy in rocks. The nondestructive testing approach proposed expands upon a technique developed recently by some of the authors for the nondestructive characterization of engineering materials and structures. The technique uses the characteristics of solitary waves propagating in a periodic array of spherical particles in contact with the rock to be characterized. The features of the waves that bounce off the chain rock interface are used to infer some properties of the geomaterial under consideration. Numerical models and experimental validation were conducted to explore the feasibility of the method and to standardize the methodology for future widespread applications.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46647081","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}
Shotcrete structures are widely used in tunnel engineering. Quality inspection is difficult, and the traditional ultrasonic testing (UT) method based on first arrival velocity has limitations. In this paper, shotcrete-rock specimens were made in a laboratory and evaluated using UT. Wavelet packet decomposition is introduced for better frequency analysis of the condition evaluation. Two methods, including calculation of the energy eigenvalues and machine learning, are used to describe the contact quality at the interface between the shotcrete and rock. The relative energy eigenvalue increases with the gradual reduction of contact quality, which can become a quantitative index of the contact quality. Machine learning performed well in the rapid recognition of discontinuities in the multiple-classification models. Both methods based on wavelet packet decomposition achieved good results in identifying discontinuities and have the potential to be used in practical engineering applications.
{"title":"Research on Ultrasonic Testing with Wavelet Packet Analysis for Shotcrete","authors":"Fei Yao, Y. Cao","doi":"10.32548/2021.me-04217","DOIUrl":"https://doi.org/10.32548/2021.me-04217","url":null,"abstract":"Shotcrete structures are widely used in tunnel engineering. Quality inspection is difficult, and the traditional ultrasonic testing (UT) method based on first arrival velocity has limitations. In this paper, shotcrete-rock specimens were made in a laboratory and evaluated using UT. Wavelet packet decomposition is introduced for better frequency analysis of the condition evaluation. Two methods, including calculation of the energy eigenvalues and machine learning, are used to describe the contact quality at the interface between the shotcrete and rock. The relative energy eigenvalue increases with the gradual reduction of contact quality, which can become a quantitative index of the contact quality. Machine learning performed well in the rapid recognition of discontinuities in the multiple-classification models. Both methods based on wavelet packet decomposition achieved good results in identifying discontinuities and have the potential to be used in practical engineering applications.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69699126","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}
Sanjaya Sahoo, Srinivas Kuchipudi, R. Rao, M. Buragohain, C. S. Chaitanya
Adhesively bonded interfaces of glass fiber– reinforced plastics (GFRP) composite to rubber and rubber to propellant were investigated for planar interfacial defects with a spatial resolution of 100 μm. Single-sided low-field nuclear magnetic resonance (NMR) with a magnetic field strength of 0.3 T (12.88 MHz proton frequency) has been used for noninvasive inspection of planar defects in GFRP-based multilayered composite structures. Further, in this paper, the application of low-field NMR for adhesive liner thickness measurement is also demonstrated. The investigation revealed applicability of single-sided low-field NMR for onsite field applications. Results were compared with other nondestructive evaluation (NDE) techniques: acousto-ultrasonic and radiographic testing (RT). It is observed that single-sided low-field NMR is an excellent NDE tool to study adhesive bonds and defects such as debonding, variations in thickness to accuracies ranging from 50 to 200 μm, and degradation. In comparison with the acousto-ultrasonic technique and RT, single-sided low-field NMR is observed to be more sensitive.
研究了玻璃纤维增强塑料(GFRP)与橡胶和橡胶与推进剂的粘接界面的平面缺陷，空间分辨率为100 μm。采用磁场强度为0.3 T (12.88 MHz质子频率)的单侧低场核磁共振(NMR)对gfrp基多层复合材料结构中的平面缺陷进行了无创检测。此外，本文还论证了低场核磁共振在胶粘剂衬里厚度测量中的应用。调查显示单面低场核磁共振适用于现场现场应用。结果比较了其他无损评价(NDE)技术:声-超声和射线检测(RT)。结果表明，单侧低场核磁共振是一种很好的无损检测工具，可用于研究粘接键和缺陷，如脱粘、厚度变化(精度范围为50 ~ 200 μm)和降解。与声-超声技术和RT技术相比，单侧低场核磁共振具有更高的灵敏度。
{"title":"Detection of Planar Defects in Multilayered GFRP Composite Structures Using Low-Field Nuclear Magnetic Resonance","authors":"Sanjaya Sahoo, Srinivas Kuchipudi, R. Rao, M. Buragohain, C. S. Chaitanya","doi":"10.32548/2021.me-04201","DOIUrl":"https://doi.org/10.32548/2021.me-04201","url":null,"abstract":"Adhesively bonded interfaces of glass fiber– reinforced plastics (GFRP) composite to rubber and rubber to propellant were investigated for planar interfacial defects with a spatial resolution of 100 μm. Single-sided low-field nuclear magnetic resonance (NMR) with a magnetic field strength of 0.3 T (12.88 MHz proton frequency) has been used for noninvasive inspection of planar defects in GFRP-based multilayered composite structures. Further, in this paper, the application of low-field NMR for adhesive liner thickness measurement is also demonstrated. The investigation revealed applicability of single-sided low-field NMR for onsite field applications. Results were compared with other nondestructive evaluation (NDE) techniques: acousto-ultrasonic and radiographic testing (RT). It is observed that single-sided low-field NMR is an excellent NDE tool to study adhesive bonds and defects such as debonding, variations in thickness to accuracies ranging from 50 to 200 μm, and degradation. In comparison with the acousto-ultrasonic technique and RT, single-sided low-field NMR is observed to be more sensitive.","PeriodicalId":49876,"journal":{"name":"Materials Evaluation","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44451652","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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