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本文从电磁超声换能器的理论入手,说明电磁超声的原理,通过电磁超声换能器的波模不同组合,进一步阐明电磁超声技术的特点和优越性,同时介绍了电磁超声在无损检测中的应用情况以及长春试验机研究所研制的CSS-133高温电磁声测厚仪。 相似文献
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为了提高高压蒸汽管道超声检测的效率,研究了超声导波在高压蒸汽管道缺陷检测中的应用。通过试验对比,设计并实践了高频导波换能器,确定了高压蒸汽管道高频导波检测灵敏度,为实现高压蒸汽管道快速检测提供了一种方法。 相似文献
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钛合金激光增材制造技术已经逐步应用于航空航天等领域中复杂构件的直接近成形制造。然而,由于特殊的制造工艺导致的高衰减性和不均匀性使其内部缺陷采用常规超声检测方法检测效率低、成像结果差,为此研究了阵列超声检测方法在增材制造钛合金构件检测中的关键技术。采用激光增材制造方法制备TC18钛合金试样,利用高频水浸超声方法分析其超声衰减特性,提出适用于增材制造钛合金构件的内部回波成像方法。基于线阵换能器全矩阵数据采集的方法分析声波沿试样不同表面入射时声波群速度随角度的变化规律,对增材制造钛合金试样的各向异性进行分析,并基于测量结果对阵列超声成像算法进行校正。分别采用线阵和环阵换能器对试样进行C扫描检测试验,分析影响检测结果的主要因素。研究结果表明,采用环阵换能器结合全聚焦算法能更精确地表征试样的内部缺陷,在增材制造钛合金构件的无损检测中有较好的应用前景。 相似文献
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线性调频脉冲压缩方法在空气耦合超声检测中的应用研究 总被引:6,自引:3,他引:6
为了提高空气耦合超声检测中的信号强度及其信噪比,研究线性调频脉冲压缩技术在空气耦合超声检测中的应用.介绍线性调频脉冲压缩技术的基本原理及其匹配滤波器的设计与实现,分析脉冲压缩参数对空气耦合超声检测结果的影响,试验研究不同激励方式对空气耦合超声换能器接收信号的影响以及脉冲压缩方法对提高信噪比的实际效果,构建空气耦合超声C扫描检测系统,对碳纤维增强复合材料板进行检测试验.研究结果表明:相对于常规脉冲激励方式,连续波激励方式可提高换能器的能量转换效率,激励信号频率特性与换能器频率特性相一致时效果最佳;应用线性调频脉冲压缩方法后,空气耦合超声检测的信噪比有了明显提高,检测效果得到了明显改善. 相似文献
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本文采用具有电子偏转及电子聚焦特性的超声相控阵技术对大口径长输管道环焊缝进行缺陷检测,克服传统无损检测由于焦点固定引起检测过程复杂的不足.相控阵换能器的声场特性决定探伤灵敏度,是换能器设计的主要依据.所以需要对超声相控阵换能器进行优化设计,其目的是研究阵元参数与声场特性之间的关系,尽可能地使主瓣尖锐,抑制栅瓣的产生,减弱旁瓣的幅度.本文首先采用数值分析方法,研究并仿真线阵参数对超声束聚焦性能的影响.然后介绍用超声相控阵换能器进行环焊缝检测的试验平台.在此基础上,选取优化后的超声相控阵探头与一个同频的常规超声探头进行对比试验.试验结果表明了该方法的有效性,能提高相控阵换能器的性能. 相似文献
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空气耦合式超声波无损检测技术的发展 总被引:10,自引:2,他引:10
空气耦合式超声波无损检测技术具有完全非接触、无损伤的特点,可用于传统超声检测手段难以适应的场合.概述空气耦合式超声检测技术的发展历程,简要分析限制该技术发展的主要技术难点,总结提高空气耦合式超声换能器效率的两种主要方法及其研究进展,介绍空气耦合式超声波无损检测技术的主要检测方法和应用领域.研究结果表明,空气耦合式超声波无损检测技术有着良好的应用前景,而高效率的超声换能器是该技术成功应用的基础,也是目前该技术领域的研究热点. 相似文献
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以我国航空航天、钢铁冶金、特种设备等领域的高温声学无损检测技术研究与应用为主线,分析了高温声学检测技术在促进先进高温材料制备与研发、钢铁冶金行业绿色低碳生产和产业升级、高温压力管道安全运行与维护等方面的巨大需求。介绍了国内外在高温声学检测的技术方法和仪器研制等方面取得的进展,分析了压电超声、电磁超声、激光超声、激光电磁超声等技术在高温无损检测应用方面存在的优缺点和应用场景,总结了高温声学检测技术面临的机遇与挑战。 相似文献
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V. N. Danilov V. M. Ushakov V. V. Mikhalev 《Russian Journal of Nondestructive Testing》2012,48(10):576-583
The results of theoretical and experimental studies of signals from high-frequency angle transducers during ultrasonic testing of thin-welded joints are presented. The effect of the quasi-bending of an acoustic beam of a piezoelectric transducer at high frequencies is confirmed. The appropriate testing parameters for such welded joints are recommended. 相似文献
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The design, fabrication, and evaluation of a high-frequency transducer made from lead-free piezoceramic for the application of microfluidic analysis is described. Barium strontium zirconate titanate [(Ba(0.95)Sr(0.05))(Zr(0.05)Ti(0.95))O(3), abbreviated as BSZT] ceramic has been chosen to be the active element of the transducer. The center frequency and bandwidth of this high-frequency ultrasound transducer have been measured to be 43 MHz and 56.1%, respectively. The transducer was integrated into a microfluidic channel and used to measure the sound velocity and attenuation of the liquid flowing in the channel. Results suggest that lead-free high-frequency transducers could be used for in situ analysis of property of the fluid flowing through the microfluidic system. 相似文献
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Investigation of the Performance of a Piezoelectric Ultrasonic Transducer by Finite Element Modeling
Mostafa Rafienezhad-Masouleh Honarvar Farhang 《Russian Journal of Nondestructive Testing》2021,57(4):269-280
Russian Journal of Nondestructive Testing - The most popular transducers used in ultrasonic testing are piezoelectric transducers. The three major components of a piezoelectric transducer are the... 相似文献
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V. K. Kachanov V. G. Kartashev I. V. Sokolov M. M. Konov E. V. Shalimova 《Russian Journal of Nondestructive Testing》2011,47(1):1-15
It is shown that the spatial distribution of the acoustic field of a broadband transducer may influence the degree of distortion
of ultrasonic signals. The principle for forming a uniform acoustic-field distribution within the directivity characteristic
of a low-frequency broadband transducer based on the chosen topology of a mosaic transducer is proposed. The comparative spatiotemporal
characteristics of mosaic broadband transducers with optimized and nonoptimized mosaic topologies are obtained as a result
of simulation. It is shown that for an optimized topology uniform field distributions can be obtained in both far- and near-field
zones of the broadband transducers. 相似文献
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基于激光测振仪的兰姆波离面和面内位移检测 总被引:2,自引:1,他引:2
激励模态和频响特性是超声导波传感器性能评估的两个重要指标,而传统的传感器,如压电传感器和电磁声传感器(Electromagnetic acoustic transducer,EMAT)等,受自身带宽和模态选择性的影响,无法有效地实现这两个参数的评估。激光测振仪可以测量结构中弹性波原始的离面和面内位移,且测量不受带宽的限制,因而是进行超声导波传感器激励模态测定和频响特性测量的理想方法之一。采用此种方法对一种周向一致激励兰姆波的EMAT进行测试,结果表明,此传感器在150~210 kHz的范围内能激励产生出单一S0模态兰姆波,在50~150 kHz范围内,A0模态与S0模态共存。利用激光测振仪检测离面和面内位移的方法,是进行传感器评估和兰姆波接收的有效方法,在超声导波的非接触测量、高温波导体检测及弹性波传播3D可视化方面也有广阔的应用前景。 相似文献
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An ultrasonic tomographic velocimeter to provide quantitative images of axial flow fields in pipes is developed and presented in this work. To detect the flow in various directions and positions, a novel transducer configuration strategy is proposed. All-in-one transducers are mounted in two sectional planes of the pipe. In each plane, N transducers are equally spaced along the circumference. Overlapped propagation paths are introduced by the configuration strategy, and the influence of the vortex flow can be eliminated theoretically by averaging the line velocities of the overlapped paths. To achieve a fast detection speed, the projection data is collected via an electrical scan in a fan-beam mode. After rearrangement and interpolation of the projection data, the parallel beam filtered back projection (FBP) algorithm is implemented to reconstruct the axial flow field. Numerical simulations with the theoretical velocity profiles were performed. The compensation method for the vortex flow is proved to be effective and necessary, and the number of transducers required for reconstruction of common flow profiles was estimated. Accordingly, an ultrasonic tomographic velocimeter consisting of 2×12 transducers was fabricated. Experiments were conducted in the straight pipe and downstream of a single bend pipe and compared with the computational fluid dynamics (CFD) simulation results. As demonstrated, the ultrasonic tomographic velocimeter was capable of visualizing both symmetric and asymmetric axial flow fields with high reliability. 相似文献
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In order to improve the measurement performance of dry calibration on ultrasonic flowmeter, the Computational Fluid Dynamic (CFD) modeling approach of the effect on transducer protrusion and recess are mainly discussed in the paper while its effects on ultrasonic flowmeter accuracy are also presented. Through comparing simulation results to experimental data, the CFD modeling is firstly determined. Then, detail analysis on flow field for two typical transducer installations are obtained based on the CFD method. Besides, the mechanism of both flow effects on measurement accuracy are explained and compared respectively, which indicates that negative velocities generated at protrusion and recess locations are the indispensable factors for negative measurement errors. Finally, comparison results show that smaller measurement error can be achieved with protruding transducers, which is a better arrangement type of transducer for ultrasonic flowmeters. 相似文献