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鉴于脉冲涡流检测和脉冲远场涡流检测在金属构件损伤检测中的优势,提出一种非铁磁性金属构件缺陷的脉冲涡流近-远场复合定量检测探头。通过数值仿真,在系统分析电磁场能流密度的基础上,研究脉冲涡流近-远场检测信号特性及其对构件腐蚀减薄缺陷的响应灵敏度,剖析检测信号特征与缺陷尺寸参数间的关联规律。同时,搭建试验平台,进一步探究基于脉冲涡流近-远场复合定量检测的非铁磁性金属构件腐蚀减薄缺陷定量检测方法。仿真及试验结果表明,所提集成磁场直接和间接耦合分量的新探头构型可同时对金属构件腐蚀减薄缺陷实施脉冲涡流检测和脉冲远场涡流检测,增强了缺陷定量信息的有效拾取。 相似文献
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对多频涡流与脉冲涡流两种不同的电磁无损检测技术的基本原理分别进行了介绍,进而从脉冲涡流的傅里叶展开式中分析了两者间的关系。指出脉冲涡流检测技术本质上等同于一种衰减型的多频涡流检测技术,而多频涡流可以认为是高频加权的脉冲涡流形式。对这两种涡流检测技术在实际生产中的应用进行了简单介绍。随着涡流检测理论的深入研究,电子技术与计算机技术的迅速发展,多频涡流和脉冲涡流检测技术将成为涡流检测的重要组成部分。 相似文献
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电磁涡流/电磁声检测[A162]韩国蒸汽发生器断管事故后强化实施蒸汽发生器管涡流检测的评定结果Myung HoSong,Ho SangShin,Suk ChullKang(韩国)[A262]根据涡流无损检测数据快速重建自然应力腐蚀裂纹NoritakaYusa,ZhenmaoChen,KenzoMiya(日本)[A447]蒸汽发生器管裂纹深度评估技术的改进Chin ChuanChao,Hung FaShyu,Ming ShengYu(中国台湾)[A491]交叉排列非磁性管间隙测量的阻抗平面分析HKJung,YSLee,DHLee(韩国)[A019]多层平面结构厚度的涡流检测PingjieHuang,ZhaotongWu(中国)[A244]通过有限元法进行时域和频域涡流仿真Che… 相似文献
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电磁(涡流)检测技术在中国——庆祝中国机械工程学会无损检测分会成立三十周年 总被引:1,自引:0,他引:1
电磁(涡流)检测具有检测速度快、灵敏度高、可进行高温检测的特点,是目前应用非常广泛,使用频率很高的检测技术,在五大常规无损检测技术中发展较快。近年来,中国经济突飞猛进,工业水平大幅度提高,电磁(涡流)检测技术也得以广泛应用。以电磁(涡流)检测技术在中国的发展历程为背景,综述了中国电磁(涡流)检测技术的发展概况。 相似文献
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Reduction of lift-off effects for pulsed eddy current NDT 总被引:8,自引:3,他引:5
The lift-off effect is commonly known to be one of the main obstacles for effective eddy current NDT testing as it can easily mask defect signals. Pulsed eddy current techniques, which are believed to be potentially rich of information, are also sensitive to the effect. An approach using normalisation and two reference signals to reduce the lift-off problem with pulsed eddy current techniques is proposed. Experimental testing on the proposed technique and results are presented in this report. Results show that significant reduction in the effect has been achieved mainly in metal loss and sub-surface slot inspection. The technique can also be applied for measurement of metal thickness beneath non-conductive coatings, microstructure, strain/stress measurement, where the output is sensitive to the lift-off effect. 相似文献
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NDT techniques for railroad wheel and gauge corner inspection 总被引:5,自引:2,他引:5
Rainer Pohl A. Erhard H. -J. Montag H. -M. Thomas H. Wüstenberg 《NDT & E International》2004,37(2):89-94
The development of non-destructive techniques (NDT) techniques for the in-service inspection of railroad wheels and gauge corners was the main activity of the NDT division VIII. 4 at BAM over the last 2 years. For such different components, two different inspection techniques were fundamentally chosen in order to fulfil the end-user requirements. Firstly the inspection of the wheels—rim and disk—should be carried out without dismantling the wheels and using ultrasonic techniques. On the other hand, the inspection of the railroad track surface at a train speed of about 70 km/h should be guaranteed using eddy current techniques. The above-mentioned tasks were a challenge for the lab staff. The accessibility for the wheel inspection was limited due to several impassable barriers such as sand tubes, etc. Eddy current application focused mainly on the detection of head check defects occurring at the gauge corner of the rail. Investigations carried out also showed, that other types of surface defects (e.g. Belgrospis, wheel burns, short-pitch corrugations, etc.) could easily be detected. Some aspects of the inspection system as well as an overview of test results are presented in the current contribution. 相似文献
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介绍了一种无损检测方法——多频远场涡流检测技术,来解决电力行业的交换器、换热器的快速在役检查。对检测原理,方案实施,缺陷评判等进行了详细说明。 相似文献
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Due to corrosive and hostile environment, in-service conductive structures are prone to subsurface corrosion which has posed a severe threat to structural integrity and safety. Although Pulsed eddy current testing (PEC) has been found advantageous over other Electromagnetic Non-destructive Evaluation (ENDE) techniques particularly in detection and characterisation of subsurface defects in conductive structures, it is subject to technical drawbacks. In light of this, in this paper, Pulse-modulation eddy current technique (PMEC) is proposed in an effort to enhance the inspection sensitivity to subsurface corrosion and quality of corrosion imaging. Closed-form expressions of PMEC responses to subsurface corrosion are formulated via the Extended Truncated Region Eigenfunction Expansion (ETREE) modelling. A series of simulations are subsequently conducted to analyse the characteristics of PMEC signals and inspection sensitivity. Following this, experiments of PMEC for evaluation and imaging of subsurface corrosion are carried out. Through theoretical and experimental investigation, it has been found that PMEC is advantageous over PEC in terms of evaluation sensitivity and quality of corrosion imaging. 相似文献
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场(厂)内机动车辆无损检测技术 总被引:1,自引:0,他引:1
场(厂)内机动车辆属于特种设备,国家对其实施强制性监督检验,而无损检测技术在确保其安全运行中扮演了重要的角色。综述了在其检验过程中分别采用的各种无损检测技术,包括目视检测、超声波检测、表面检测以及噪声测试、速度测试、转向测试和液压系统测试等,并阐述了采用这些检测技术的目的。 相似文献
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电磁超声检测技术由于无需媒介以及与被测物体非接触,不但可提高检测效率,而且可将超声检测技术的应用扩展到高温、高速和在线检测。根据电磁超声传感器的工作原理,建立了基于有限元的电磁超声无损检测数值分析方法,开发了相应的计算程序,验证了其有效性。应用开发的电磁超声数值模拟程序,研究了不同激励方式对电磁超声波的影响,得到了相应超声波在均匀各向同性金属介质中的传播过程。该计算方法和程序为实际电磁超声检测中缺陷的定量和探头优化提供了手段。 相似文献
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中国无损检测与评价技术的进展 总被引:1,自引:0,他引:1
无损检测与评价技术在我国日常产品质量检验和大量在用工业和民用设备的检验中发挥了十分重要的作用。综述了我国无损检测与评价技术发展的历史、人员的培训和认证体系及统计、学术会议和仪器展览情况、标准现状、仪器的生产和销售状况、人员教育现状、目前的主要研究和应用领域。从统计结果看,我国拥有近17万无损检测人员和2000多家无损检测机构,2007年无损检测仪器的销售额达10亿元人民币左右,大专院校每年培养近千名无损检测专业的大专、本科和研究生。我国不仅对常规无损检测设备、器材和服务有着巨大的需求,而且对先进的无损检测仪器、技术和服务也有大量的需求。我国已成为一个无损检测仪器、技术和服务的巨大市场。我国的无损检测工作者已经在许多技术和领域进行了大量的研究、开发和成功的应用。 相似文献
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压力容器无损检测技术综述 总被引:17,自引:3,他引:17
综述压力容器原材料、压力容器制造和使用过程中采用的无损检测技术,包括超声、射线、磁粉、渗透、涡流、声发射、红外线、漏磁和磁记忆检测技术。并论述采用这些检测技术的目的。 相似文献