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应用脉冲涡流检测金属表面裂纹的研究 总被引:1,自引:0,他引:1
脉冲涡流检测方法是涡流检测技术的一个新兴的分支.本文介绍了脉冲涡流检测技术应用于检测金属表面裂纹.实验结果表明:经综合考虑了裂纹深度、材质对测量结果的影响之后,发现裂纹深度和涡流信号幅值峰值之间有着深远的关联.借此可以初步的量化的判断裂纹深度. 相似文献
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脉冲涡流无损检测技术对矩形截面形状的裂纹具有良好的定量检测能力,但是,实际检测过程中遇到的裂纹缺陷的形状非常复杂,本文在前期工作的基础上,进一步研究了脉冲涡流对其它截面形状裂纹的定量检测问题,实验结果表明以前针对矩形裂纹的方法也完全适用于其它截面形状裂纹的定量检测。 相似文献
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用变频扫描励磁方法定量检测裂纹 总被引:5,自引:0,他引:5
目的 实现对疵病的定量检测和对材料的定性检测。方法 通过改变磁场交变频率从而引致导体中的涡流发生变化,来观测工件材料的疵病。结果 实验证明文该方法对于提高检测精度是有效的。结论 用变频扫描励磁方法进行裂纹定量检测可提高检测的可靠性。 相似文献
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基于集成霍尔传感器的脉冲涡流无损检测装置 总被引:2,自引:1,他引:1
脉冲涡流是近几年新发展起来的一种无损检测技术 ,与传统涡流不同 ,脉冲涡流通过测量磁场最大值出现的时间来确定缺陷的位置。本文采用集成霍尔传感器来对脉冲涡流产生的磁场进行测量 ,试验结果证明集成霍尔传感器使用简单、灵敏度高 ,适于在低频时对弱磁场进行定量检测。 相似文献
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提出了一种基于预多频涡流检测技术的钢球硬度分选系统,介绍了系统组成、工作原理及硬软件设计。该系统以工业控制PC机为核心,采用8个频率工作,通过对每个频率的测量信号的综合评价,可确定钢球的硬度。试验和实际生产应用均证明该系统可对钢球硬度进行100%自动分选,且灵敏度高,可靠性好。 相似文献
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Fatigue cracks are prone to develop around fasteners found in multilayer aluminum structures on aging aircraft. Probability of detection (POD) studies using eddy current techniques within the bolt holes contribute to risk assessments used in evaluating the serviceability of these aircraft. Signal response to corner and mid-bore cracks by eddy current testing using standard split-D differential probes has been examined for in-service material from the horizontal stabilizer of a Hercules aircraft. Results are compared to data obtained from laboratory samples with drilled holes. Based on a logistic regression analysis, the results show no significant difference for a90/95 (90% of the cracks of size a will be detected 95% of the time) for mid-bore crack length of 0.60 mm in this study compared to 0.62 mm in earlier work on drilled holes. However, there was a substantial loss of sensitivity for corner cracks. In this study on in-service material, the a90/95 for corner cracks was 0.82 mm compared to 0.31 mm obtained from drilled holes. Decrease in sensitivity was attributed to damage at the hole’s corners of the in-service material, including rounding, folded metal, and burrs. Hole damage also significantly increased the risk of a false call. 相似文献
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曲面间隙测量电涡流传感器探头的性能研究 总被引:1,自引:0,他引:1
针对曲面间间隙测量的实际应用,从电涡流传感器的检测原理出发,对传感器探头的测量性能进行了研究.在平面线圈磁场分布计算的基础上,通过修正得到了曲面线圈的磁场分布规律,进而对线圈的测试性能进行分析和预测,实现了线圈参数的优化设计.同时,对曲面测量的各种影响因素进行了分析和试验验证,为电涡流传感器应用于曲面测量提供参考和依据. 相似文献
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S.-C. Wooh 《Research in Nondestructive Evaluation》2013,24(3):145-166
Abstract This paper presents a novel concept based on the acoustic Doppler effect for detecting defects on the surface of a rapidly moving object. The proof-of-concept tests show the feasibility of this approach. By impinging and detecting airborne ultrasound on a rotating target with surface notches, the Doppler effect was clearly observed in the spectral domain at the time when the transducer passed over the flawed zone. For continuous monitoring, the gated spectral magnitude is used to discriminate the signals returned from a flawed region against those from sound regions. In addition, two real-time signal processing techniques are proposed. 相似文献
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结合实际涡流无损检测应用中的含磁介质点探头的特点,分析了探头中磁介质引入的各种附加效应及其对缺陷阻抗的影响。通过引入等效电流的概念,讨论了磁介质对涡流场的作用,建立含磁介质点探头涡流无损检测模型,并给出含磁介质探头周围的电磁场方程,求得均匀半无限导体系统的磁矢量势分布和导体中涡流、电场强度分布。通过实例,计算了非铁磁性导体中无缺陷时探头信号与提离高度的关系、存在缺陷时探头阻抗变化的特点。理论计算与实验结果基本吻合。 相似文献