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Excitation and Detection of Shear Horizontal Waves with Electromagnetic Acoustic Transducers for Nondestructive Testing of Plates 被引量:13
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作者 MA Qingzeng JIAO Jingpin +3 位作者 HU Ping ZHONG Xi WU Bin HE Cunfu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第2期428-436,共9页
The fundamental shear horizontal(SH0) wave has several unique features that are attractive for long-range nondestructive testing(NDT). By a careful design of the geometric configuration, electromagnetic acoustic t... The fundamental shear horizontal(SH0) wave has several unique features that are attractive for long-range nondestructive testing(NDT). By a careful design of the geometric configuration, electromagnetic acoustic transducers(EMATs) have the capability to generate a wide range of guided wave modes, such as Lamb waves and shear-horizontal(SH) waves in plates. However, the performance of EMATs is influenced by their parameters. To evaluate the performance of periodic permanent magnet(PPM) EMATs, a distributed-line-source model is developed to calculate the angular acoustic field cross-section in the far-field. Numerical analysis is conducted to investigate the performance of such EMATs with different geometric parameters, such as period and number of magnet arrays, and inner and outer coil widths. Such parameters have a great influence on the directivity of the generated SH0 waves that arises mainly in the amplitude and width of both main and side lobes. According to the numerical analysis, these parameters are optimized to obtain better directivity. Optimized PPM EMATs are designed and used for NDT of strip plates. Experimental results show that the lateral boundary of the strip plate has no perceivable influence on SHO-wave propagation, thus validating their used in NDT. The proposed model predicts the radiation pattern ofPPM EMATs, and can be used for their parameter optimization. 展开更多
关键词 electromagnetic acoustic transducers shear-horizontal waves strip plate nondestructive testing
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Nondestructive Testing and Characterization of Residual Stress Field Using an Ultrasonic Method 被引量:33
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作者 SONG Wentao XU Chunguang +1 位作者 PAN Qinxue SONG Jianfeng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第2期365-371,共7页
To address the difficulty in testing and calibrating the stress gradient in the depth direction of mechanical components, a new technology of nondestructive testing and characterization of the residual stress gradient... To address the difficulty in testing and calibrating the stress gradient in the depth direction of mechanical components, a new technology of nondestructive testing and characterization of the residual stress gradient field by ultrasonic method is proposed based on acoustoelasticity theory. By carrying out theoretical analysis, the sensitivity coefficients of different types of ultrasonic are obtained by taking the low carbon steel(12%C) as a research object. By fixing the interval distance between sending and receiving transducers, the mathematical expressions of the change of stress and the variation of time are established. To design one sending-one receiving and oblique incidence ultrasonic detection probes, according to Snell law, the critically refracted longitudinal wave(LCR wave) is excited at a certain depth of the fixed distance of the tested components. Then, the relationship between the depth of LCR wave detection and the center frequency of the probe in Q235 steel is obtained through experimental study. To detect the stress gradient in the depth direction, a stress gradient LCR wave detection model is established, through which the stress gradient formula is derived by the relationship between center frequency and detecting depth. A C-shaped stress specimen of Q235 steel is designed to conduct stress loading tests, and the stress is measured with the five group probes at different center frequencies. The accuracy of ultrasonic testing is verified by X-ray stress analyzer. The stress value of each specific depth is calculated using the stress gradient formula. Accordingly, the ultrasonic characterization of residual stress field is realized. Characterization results show that the stress gradient distribution is consistent with the simulation in ANSYS. The new technology can be widely applied in the detection of the residual stress gradient field caused by mechanical processing, such as welding and shot peening. 展开更多
关键词 ultrasonic nondestructive testing acoustoelasticity theory residual stress field stress gradient ultrasonic characterization
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Statistical analysis of nondestructive testing results of cast steel joints in civil engineering structures 被引量:4
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作者 Cheng Jiaming Gao Yiqi +2 位作者 Yan Huadong Sun Sijia Jin Hui 《Journal of Southeast University(English Edition)》 EI CAS 2022年第1期1-8,共8页
To study the distribution law and random characteristics of casting defects in steel castings,24 civil engineering structural cast steel joints were divided into two groups:simple cast steel joints and complex cast st... To study the distribution law and random characteristics of casting defects in steel castings,24 civil engineering structural cast steel joints were divided into two groups:simple cast steel joints and complex cast steel joints.Three kinds of nondestructive testing(NDT)methods,namely,visual,magnetic particle,and ultrasonic inspections,were used to detect the macroscopic defects in joints.The NDT results were then statistically analyzed.The results show that the unfused core support is a common defect of complex cast steel joints,and the defect can be seen visually,so excavation and repair welding should be carried out before castings leave factories.Casting cracks are extremely likely to occur in the intersection area of tubes,which is called the ultrasonic inspection blind zone.The occurrence probability of gas pores on simple cast steel joints is the largest,and the occurrence probability of core support incomplete fusions on complex cast steel joints is the largest.However,when cast steel joints are counted as a whole sample,the occurrence probability of gas pores is larger than that of core support incomplete fusions.Therefore,it is the most common defect in cast steel joints. 展开更多
关键词 steel casting casting defect nondestructive testing statistical analysis
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Nondestructive testing method of wood moisture content based on a planar capacitance sensor model 被引量:3
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作者 WANG Jue LUO Yue-sheng LIU Shao-gang 《Forestry Studies in China》 CAS 2010年第3期142-146,共5页
For our research, a new hybrid experimental-computational method is presented. We applied a least squares fitting method (LSFM) to reconstruct the wood moisture content (WMC) from the data measured with a planar c... For our research, a new hybrid experimental-computational method is presented. We applied a least squares fitting method (LSFM) to reconstruct the wood moisture content (WMC) from the data measured with a planar capacitance sensor. A boundary element method (BEM) was used to compute the relationship between capacitance and the dielectric constant. A functional relationship between MC and the dielectric constant was identified by LSFM. The agreement of this final computation result with the experimental data indicates that this method can be used to estimate the WMC quickly and effectively with engineering analysis. Compared with popular statistical methods, a large number of experiments are avoided, some costs of testing are reduced and the efficiency of testing is enhanced. 展开更多
关键词 planar capacitance sensor nondestructive testing wood moisture content boundary element method least squares fitring method
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Recent developments in photoacoustic imaging and sensing for nondestructive testing and evaluation 被引量:2
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作者 Sung-Liang Chen Chao Tian 《Visual Computing for Industry,Biomedicine,and Art》 EI 2021年第1期50-62,共13页
Photoacoustic(PA)imaging has been widely used in biomedical research and preclinical studies during the past two decades.It has also been explored for nondestructive testing and evaluation(NDT/E)and for industrial app... Photoacoustic(PA)imaging has been widely used in biomedical research and preclinical studies during the past two decades.It has also been explored for nondestructive testing and evaluation(NDT/E)and for industrial applications.This paper describes the basic principles of PA technology for NDT/E and its applications in recent years.PA technology for NDT/E includes the use of a modulated continuous-wave laser and a pulsed laser for PA wave excitation,PA-generated ultrasonic waves,and all-optical PA wave excitation and detection.PA technology for NDT/E has demonstrated broad applications,including the imaging of railway cracks and defects,the imaging of Li metal batteries,the measurements of the porosity and Young’s modulus,the detection of defects and damage in silicon wafers,and a visualization of underdrawings in paintings. 展开更多
关键词 Photoacoustic imaging Photoacoustic sensing nondestructive testing nondestructive evaluation Photoacoustic microscopy
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Dynamic Elastic Modulus of Cement Paste at Early Age based on Nondestructive Test and Multiscale Prediction Model 被引量:1
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作者 赵海涛 黄冬辉 +1 位作者 WANG Xiaojun CHEN Xudong 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第2期321-328,共8页
This paper introduced a nondestructive testing method to evaluate the dynamic elastic modulus of cement paste. Moreover, the effect of water-cement ratio and conventional admixtures on the dynamic elastic modulus of c... This paper introduced a nondestructive testing method to evaluate the dynamic elastic modulus of cement paste. Moreover, the effect of water-cement ratio and conventional admixtures on the dynamic elastic modulus of cement paste was investigated, in which three kinds of admixtures were taken into account including viscosity modifying admixture (VMA), silica.fume (SF), and shrinkage-reducing admixture (SRA). The experimental results indicate that the dynamic elastic modulus of cement paste increases with decreasing water-cement ratio. The addition of SF increases the dynamic elastic modulus, however, the overdosage of VMA causes its reduction. SRA reduces the dynamic elastic modulus at early age without affecting it in later period. Finally, a multiscale micromechanics approach coupled with a hydration model CEMHYD3D and percolation theory is utilized to predict the elastic modulus of cement paste, and the predictive results by the model are in accordance with the experimental data. 展开更多
关键词 dynamic elastic modulus nondestructive test viscosity modifying admixture silica fume shrinkage-reducing admixture multiscale model
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The Application of Impact Echo Scanning on Nondestructive Test of Pavement 被引量:1
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作者 张建纲 水中和 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2006年第z1期123-126,共4页
A new nondestructive test method-Impact Echo Scanning was introduced. Application of this method on pavement structure test was discussed. A method to increase the measurement accuracy of the test on multi-layers was ... A new nondestructive test method-Impact Echo Scanning was introduced. Application of this method on pavement structure test was discussed. A method to increase the measurement accuracy of the test on multi-layers was proposed, and was verified by field test. The test results show that the basic structural information can obtained rapidly and accurately by 3-D scanning of the impact echo system. 展开更多
关键词 impact echo scanning nondestructive test pavement structure three dimension imaging
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Ultrasonic Nondestructive Testing of Superplastic Solid-State Welding Joint for Different Steels 被引量:1
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作者 ZHANG Ke-ke YANG Yun-lin +1 位作者 CHEN Huai-dong XUE Jin 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2002年第2期58-61,共4页
Based on quantitative microscopic examinations of welds and welding rate for different steels(40Cr and T10A) joint,which possess the ultra-fine microstructure after high frequency hardening(HFH) and salt-bath cyclic q... Based on quantitative microscopic examinations of welds and welding rate for different steels(40Cr and T10A) joint,which possess the ultra-fine microstructure after high frequency hardening(HFH) and salt-bath cyclic quenching(SCQ),the suitable defect grey scale threshold value was determined,and the welding rate of superplastic solid-state welding of different steels(40Cr and T10 A steel) was systematically inspected and analyzed by means of self-made ultrasonic imaging inspection system.The experimental results showed that the superplastic solid-state weld of different steels can be inspected more accurately,reliably and quickly by this system,and the results were in good accordance with that of metallographic observation.The welding rate of superplastic welding is in linear relation with tensile strength of joint. 展开更多
关键词 superplastic solid-state welding welding rate ultrasonic nondestructive testing
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Investigation of Eddy Current Nondestructive Testing for Carbon Fiber-Reinforced Plastic (CFRP) Based on Electromagnetic Field Analysis 被引量:1
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作者 Tomonori Hongu Kiyoshi Koyama Junichi Toriumi 《Journal of Mechanics Engineering and Automation》 2018年第3期127-131,共5页
CFRP (carbon fiber reinforced plastic) is used extensively in aircraft and spacecraft structures, because of its excellent mechanical properties. Ultrasonic testing, which is used as a non-destructive testing techni... CFRP (carbon fiber reinforced plastic) is used extensively in aircraft and spacecraft structures, because of its excellent mechanical properties. Ultrasonic testing, which is used as a non-destructive testing technique for CFRP, requires a contact medium. In contrast, eddy current testing does not require a contact medium, and when used for CFRP testing it has advantages not available with other techniques. CFRP is a laminate, with each layer being anisotropically conductive, and the distribution of the induced eddy current is yet to be determined. Here, to determine the eddy current distribution in the detection of flaws in cross-ply CFRP (0°/90°) by using a cross-point probe, we performed an FEM (finite element method) analysis of electromagnetic fields. We investigated the nature of the flaw signals and the differences in eddy current distributions between materials with and without flaws. 展开更多
关键词 nondestructive testing eddy current testing CFRP flaw detection FEM analysis.
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Rolling contact fatigue nondestructive testing system for a bearing inner ring based on initial permeability
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作者 Dai Xianze Shuai Liguo Liu Jie 《Journal of Southeast University(English Edition)》 EI CAS 2019年第3期310-317,共8页
Due to the fact that rolling contact fatigue is not easily detected, and residual life is not easily evaluated in the early stage of bearing life, a nondestructive testing method based on initial permeability is propo... Due to the fact that rolling contact fatigue is not easily detected, and residual life is not easily evaluated in the early stage of bearing life, a nondestructive testing method based on initial permeability is proposed. By analyzing the crack propagation mechanism, a fatigue state detection system based on differential signals is designed. A simulation model of the detection of the inner ring of the pulse signal is established by using the electromagnetic field simulation software. The effects of the height of the coil, the inner and outer diameter, the number of coil turns, the diameter and the height of the ferrite core of the probe on the differential value of the detection signal are simulated. The parameter combination of the maximum difference value of the signal is used as the structural size of the sensor, and the detection sensor is designed and fabricated. Moreover, the bearing fatigue test system is designed, and the bearing is tested. The results show that the system has good detection ability for rolling contact fatigue and verifies the mechanism and trend of crack propagation in the inner ring of the bearing. 展开更多
关键词 initial permeability nondestructive testing rolling contact fatigue.
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Compressive Strength Prediction of Porous Concrete Using Nondestructive Tests
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作者 Young Sang Cho Jeom Han Kim Sung Uk Hong 《Journal of Civil Engineering and Architecture》 2011年第12期1053-1064,共12页
This research focused on a prediction of compressive strength in porous concrete based on the ratio of air-entrained agents in the concrete slab using nondestructive testing methods such as the Impact Echo (IE) meth... This research focused on a prediction of compressive strength in porous concrete based on the ratio of air-entrained agents in the concrete slab using nondestructive testing methods such as the Impact Echo (IE) method, Spectral Analysis of Surface Wave (SASW) method and Free-Free Resonance (FFR) test. The method that best predicts the strength of the concrete slab can be derived from a relationship between compressive strengths and stress wave velocities. Concrete slab specimens of varying air content, were formed with a mix ratio of air-entrained agent of 0%, 0.15%, 0.3%, 0.7% and 1.5% by weight. These slabs were tested and analyzed to measure the stress wave velocities in order to develop a correlation with compressive strengths. The plot between the stress waves and compressive strengths showed a stiffslope up to an air ratio of 4% with a less steep slope beyond this point. In the process of predicting the compressive strength of concrete slab specimens, the prediction of compressive strength based on the compression wave velocity caused an average error of 4.9% in the compression wave velocity, and the prediction of compressive strength based on the surface wave velocity caused an average error of 2.2% in the surface wave velocity. 展开更多
关键词 nondestructive test impact echo method SASW method free-free resonance test compressive strength air contents
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Breakthrough Made on the Nondestructive Testing of Orbital Spacecraft
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《Aerospace China》 2012年第4期23-23,共1页
Lanzhou Institute of Physics, a subsidiary of CAST, conducted ground testing on its newly developed eddy current nondestructive testing equipment, demonstrating an important breakthrough had been made with the nondest... Lanzhou Institute of Physics, a subsidiary of CAST, conducted ground testing on its newly developed eddy current nondestructive testing equipment, demonstrating an important breakthrough had been made with the nondestructive testing of orbital spacecraft. The equipment works steadily and has met the design requirements for space applications. It was also announced by the Institute that the equipment would be used during the next lunar exploration mission to detect the status of 展开更多
关键词 Breakthrough Made on the nondestructive testing of Orbital Spacecraft
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Enhanced air-coupled impact echo technique by phase analysis of signals from multiple sensors
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作者 Najjiya Almallah Nenad Gucunski 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2024年第2期297-310,共14页
This paper presents an air-coupled impact echo(IE)technique that relies on the phase spectrum of the collected data to find the frequencies corresponding to the reflections from delaminations.The proposed technique ta... This paper presents an air-coupled impact echo(IE)technique that relies on the phase spectrum of the collected data to find the frequencies corresponding to the reflections from delaminations.The proposed technique takes advantage of the fact that the IE compression wave is not a propagating wave,but it is the 1st order symmetrical(S1)mode Lamb wave at zero group velocity(S1-ZGV).Therefore,it searches the phase spectra of the data collected by multiple sensors to locate the frequency corresponding to the lowest phase difference.As a result,the technique reduces the effect of propagating waves,including the direct acoustic wave and ambient noise.It is named the Constant Phase IE(CPIE).The performance of the CPIE is experimentally compared with the regular amplitude spectrum-based IE technique and two other multisensor IE techniques.The CPIE shows a performance advantage,especially in a noisy environment. 展开更多
关键词 nondestructive testing(NDT) nondestructive evaluation(NDE) bridge inspection bridge evaluation impact echo bridge delamination concrete bridge deck air-coupled sensing MEMS
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Assessing efficacy of standard impregnation techniques on die-cast aluminum alloys using X-ray micro-CT
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作者 Ajith Bandara Koichi Kan +3 位作者 Katanaga Yusuke Natsuto Soga Akifumi Koike Toru Aoki 《China Foundry》 SCIE EI CAS CSCD 2024年第3期276-286,共11页
Utilizing lightweight Al alloys in various industrial applications requires achieving precise pressure tightness and leak requirements.Vacuum pressure impregnation(VPI)with thermosetting polymers is commonly used to a... Utilizing lightweight Al alloys in various industrial applications requires achieving precise pressure tightness and leak requirements.Vacuum pressure impregnation(VPI)with thermosetting polymers is commonly used to address leakage defects in die-cast Al alloys.In this study,the efficacy of the VPI technique in sealing alloy parts was investigated using a combination of nondestructive micro X-ray computed tomography(micro XCT)and a standard leak test.The results demonstrate that the commonly used water leak test is insufficient for determining the sealing performance.Instead,micro XCT shows distinct advantages by enabling more comprehensive analysis.It reveals the presence of a low atomic number impregnates sealant within casting defects,which has low grey contrast and allows for visualizing primary leakage paths in 3D.The effective atomic number of impregnated resin is 6.75 and that of Al alloy is 13.69 by dual-energy X-ray CT.This research findings will contribute to enhancing the standard VPI process parameters and the properties of impregnating sealants to improve quality assurance for impregnation in industrial metals. 展开更多
关键词 nondestructive testing Al alloy die-casting vacuum pressure impregnation micro X-ray computed tomography duel-energy X-ray CT
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Femtosecond laser-acoustic modeling and simulation for AlCu nanofilm nondestructive testing
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作者 Zhongyu WANG Jing MIN +4 位作者 Jing HU Zehan WANG Xiuguo CHEN Zirong TANG Shiyuan LIU 《Frontiers of Mechanical Engineering》 SCIE CSCD 2024年第5期59-71,共13页
Photoacoustic detection has shown excellent performance in measuring thickness and detecting defects in metal nanofilms.However,existing research on ultrafast lasers mainly focuses on using picosecond or nanosecond la... Photoacoustic detection has shown excellent performance in measuring thickness and detecting defects in metal nanofilms.However,existing research on ultrafast lasers mainly focuses on using picosecond or nanosecond lasers for large-scale material processing and measurement.The theoretical study of femtosecond laser sources for photoacoustic nondestructive testing(NDT)in nanoscale thin film materials receives much less emphasis,leading to a lack of a complete physical model that covers the entire process from excitation to measurement.In this study,we developed a comprehensive physical model that combines the two-temperature model with the acoustic wave generation and detection model.On the basis of the physical model,we established a simulation model to visualize the ultrafast lasermaterial interaction process.The damage threshold of the laser source is determined,and the effect of key parameters(laser fluence,pulse duration,and wavelength)for AlCu nanofilms on the femtosecond photoacoustic NDT process is discussed using numerical results from the finite element model.The numerical results under certain parameters show good agreement with the experimental results. 展开更多
关键词 femtosecond photoacoustic nondestructive testing metal nanofilm ultrafast laser-matter interaction modeling and simulation semiconductor manufacturing
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Linear and Nonlinear Ultrasonic Detections of Impact Damage in Composite Laminate
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作者 WANG Rong WU Qi +1 位作者 ZHANG Guitao XIA Guochun 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2024年第5期599-608,共10页
The appearance and accumulation of internal impact damage seriously influence overall performance of carbon fiber reinforced plastic(CFRP).Thus,this study evaluates the change in impact damage number by using linear a... The appearance and accumulation of internal impact damage seriously influence overall performance of carbon fiber reinforced plastic(CFRP).Thus,this study evaluates the change in impact damage number by using linear and nonlinear ultrasonic Lamb wave detection methods,and compares these two detection results.An ultrasonic wave simulation model for composite structure with impact damage is established using the finite element method,and the interaction between impact damage and the ultrasonic wave is simulated.Simulation results demonstrate that the ultrasonic amplitude linearly decreases,and the relative nonlinear parameter linearly increases in proportion to the impact number,respectively.The linear-fitting slope of nonlinear parameter is 0.38 per impact number at an input frequency of 1.0 MHz.It is far higher than that of the linear ultrasonic amplitude,which is only-0.12.However,with the increase of impact damage,the linear growth of nonlinear parameters mainly depends on the decrease in ultrasonic amplitude rather than the accumulation of second harmonic amplitude.In the linear ultrasonic amplitude detection,the linear fitting slope at 1.1 MHz is-0.14,which is lower than those at 0.9 MHz and 1.0 MHz.Meanwhile,in the nonlinear ultrasonic parameter detection,the linear fitting slope at 1.1 MHz is 0.92,which is higher than those at 0.9 MHz and 1.0 MHz.The results show that higher frequencies lead to greater attenuation of ultrasonic amplitude and a larger increase in nonlinear parameters,which can enhance the sensitivity of both linear and nonlinear ultrasonic detections.The accuracy of simulation results is demonstrated through the low-velocity impact and ultrasonic experiments.The results show that compared with nonlinear ultrasonic technology,the linear ultrasonic technology is more suitable for impact damage assessment of carbon fiber reinforced plastic because of its simpler detection process and higher sensitivity. 展开更多
关键词 carbon fiber reinforced plastic(CFRP) nonlinear ultrasonic Lamb wave impact damage nondestructive testing
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Modeling and finite element analysis of transduction process of electromagnetic acoustic transducers for nonferromagnetic metal material testing 被引量:13
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作者 郝宽胜 黄松岭 +2 位作者 赵伟 段汝娇 王珅 《Journal of Central South University》 SCIE EI CAS 2011年第3期749-754,共6页
Facing the problems lack of considering the non-uniform distribution of the static bias magnetic field and computing the panicle displacements in the simulation model of electromagnetic acoustic transducer (EMAT), a... Facing the problems lack of considering the non-uniform distribution of the static bias magnetic field and computing the panicle displacements in the simulation model of electromagnetic acoustic transducer (EMAT), a multi-field coupled model was established and the finite element method (FEM) was presented to calculate the entire transduction process. The multi-field coupled model included the static magnetic field, pulsed eddy current field and mechanical field. The FEM equations of the three fields were derived by Garlerkin FEM method. Thus, the entire transduction process of the EMAT was calculated through sequentially coupling the three fields. The transduction process of a Lamb wave EMAT was calculated according to the present model and method. The results show that, by the present method, it is valid to calculate the particle displacement under the given excitation signal and non-uniformly distributed static magnetic field. Calculation error will be brought about if the non-uniform distribution of the static bias magnetic field is neglected. 展开更多
关键词 metal material nondestructive testing electromagnetic acoustic transducer multi-field coupling Garlerkin method finite element
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A Dynamics Study of a Magnetic Flux Leakage(MFL) Signal and its Application to Defect Location Discrimination in Steel Pipes MFL Testing Equipment 被引量:1
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作者 KANG Yi-hua LI Jiu-zheng WU Xin-jun 《International Journal of Plant Engineering and Management》 2009年第2期70-77,共8页
Difference processing was used to the direct current magnetic flux leakage (DC-MFL) signal, emanating from the defects machined artificially on the internal and external surfaces of a steel pipe. Consequently, the l... Difference processing was used to the direct current magnetic flux leakage (DC-MFL) signal, emanating from the defects machined artificially on the internal and external surfaces of a steel pipe. Consequently, the loea-tion discriminating index 8 was provided to identify the defect whether it is on the internal surface or the external one. Three characteristics, shape, depth and orientation of the defect, were discussed through a series of experiments on the artificial defects, such as transverse notches, oblique notches and pits on the steel pipe. The approach has been verified effective to address the defect location identifying problem, albeit the limits on the accuracy assessment to those natural defects on steel pipes in service. 展开更多
关键词 nondestructive testing magnetic flux leakage steel pipes internal defects
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Health condition monitoring with multiple physical signals in tensile test for double-material friction welding
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作者 张玉波 徐滨士 +2 位作者 王海斗 杨大祥 朱丽娜 《Journal of Central South University》 SCIE EI CAS 2012年第10期2705-2711,共7页
The manifold physical signals including micro resistance,infrared thermal signal and acoustic emission signal in the tensile test for double-material friction welding normative samples were monitored and collected dyn... The manifold physical signals including micro resistance,infrared thermal signal and acoustic emission signal in the tensile test for double-material friction welding normative samples were monitored and collected dynamically by TH2512 micro resistance measuring apparatus,flir infrared thermal camera and acoustic emission equipment which possesses 18 bit PCI-2 data acquisition board.Applied acoustic emission and thermal infrared NDT(non-destructive testing) means were used to verify the feasibility of using resistance method and to monitor dynamic damage of the samples.The research of the dynamic monitoring system was carried out with multi-information fusion including resistance,infrared and acoustic emission.The results show that the resistance signal,infrared signal and acoustic emission signal collected synchronously in the injury process of samples have a good mapping.Electrical,thermal and acoustic signals can more accurately capture initiation and development of micro-defects in the sample.Using dynamic micro-resistance method to monitor damage is possible.The method of multi-information fusion monitoring damage possesses higher reliability,which makes the establishing of health condition diagnosing and early warning platform with multiple physical information monitoring possible. 展开更多
关键词 micro resistance pictorial infrared photography acoustic emission nondestructive testing dynamic monitoring
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Determination of discontinuities in marble blocks via a nondestructive ultrasonic technique
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作者 Ahmet Hakan Onur Sefa Bakrac 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2009年第5期487-493,共7页
Miners working in the marble industry have always been interested in identifying structural weaknesses in marble blocks before they are transported to marble processing plants. To achieve this difficult task, several ... Miners working in the marble industry have always been interested in identifying structural weaknesses in marble blocks before they are transported to marble processing plants. To achieve this difficult task, several simple methods have been developed among miners but observation-based methods do not consistently provide satisfactory results. A nondestructive method developed for testing concrete could be used for this purpose. In this study, this simple method based on differences in ultrasonic wave propagation in different materials was presented, and the test results performed both in the laboratory and a marble quarry were discussed. 展开更多
关键词 nondestructive test MARBLE DISCONTINUITY ultrasonic wave
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