超声波探伤仪在高速钢轨检测中的应用

为了满足钢轨生产的需要,作者主持开发了一套钢轨在线超声探伤系统。三年多的运行结果表明,这套设备性能良好。本文简要地介绍这套设备的各个组成部分,包括超声探头、超声探伤仪、扫查机械和电控系统。同时还介绍了过去三年系统的运行情况和探伤检验的结果。     

Ultrasonic Multichannel Flaw Detector for Testing Rails with Signal Recording

Although automated testing instruments have been introduced intensely on the railways of Russia, up to 95% of hazardous flaws in rails are detected by ultrasonic two-line (removable) flaw detectors. The paper describes the functional diagram and basic functions of an ultrasonic detector of the new generation, AVIKON-01, with continuous recording of data. The instrument is supplied with the software package for analysis of testing results, and it has advantages of both hand-held removable flaw detectors and high-performance instruments for nondestructive testing of rails.     

摩擦焊接头的超声检测模型及其在检测中的应用

摩擦焊接头中的弱结合是一种用常规无损探伤方法无法检测到的缺陷，具有很大的危害性，给出了摩擦焊接头超声检测的一种数学模型，根据模型发现不同质量的摩擦焊接头其回波信号的幅值－频率特性有明显的区别。     

超声红外热像技术中预紧力对金属平板振动特性的影响

在超声红外热像检测过程中,超声脉冲激励下被测对象的振动状态直接决定了缺陷区域的生热效果,而工具杆与被测对象之间的预紧力是影响被测对象振动状态的重要因素之一。试验结果表明:预紧力的增大使得振动能量呈上升趋势并伴随着小范围不稳定,同时被测对象的振动频谱由混沌振动开始,经历次谐波、准次谐波后达到超谐波振动状态。针对上述现象,采用显式动力学方法建立了与试验条件相对应的有限元模型,并进行了瞬态动力学分析。模型采用压电-力类比方法来模拟压电陶瓷的逆压电效应,同时引入了动态松弛来更准确模拟试验工况。仿真结果验证了试验观察到的现象,并进一步揭示了预紧力的增大将改变超声工具杆和被测平板之间的接触力状态,从而改变被测试件的振动能量分布和振动频谱。研究成果有助于实现通过预紧力来控制被测对象振动状态,进而达到优化超声红外热像检测的目的。     

Process design for the hot forging of asymmetric rail to symmetric rail

The process design of hot forging, asymmetric to symmetric rib-web shaped steel, which is used for the turnout of express rails has been studied. Owing to the great difference in shape between the initial billet and the final forged product, it is impossible to hot forge the rail in a single stage operation. The numerical simulation for hot forging of asymmetric shape to symmetric shape was carried out by using commercial FEM code, DEFORMTM-2D. For comparison with the simulation results, a experiment of flow analysis using plasticine was also carried out. The results of the flow experiment showed good agreement with those of the simulation.     

Issues of ultrasonic testing of extended complexly structured items with strong attenuation of signals

These and subsequent articles present the results of the studies of interference resistant methods and devices for ultrasonic testing of extended items made of complexly structured materials. The presented results are based on the radio-engineering R &; D that have been conducted for over 30 years by the Department of Electronic Devices of the Moscow Power Engineering Institute. The studies are concurrently focused on the development of methods for separating echo signals from white and structural noise, on the application of complexly modulated signals, on the development of spatial and temporal methods for processing signals, on the development of broadband mosaic transducers, and on the design of multifunctional devices for ultrasonic testing. The necessity of such a comprehensive approach to ultrasonic testing is substantiated in this article by analysis of the problems of ultrasonic testing of complexly structured items with strong integral attenuation of ultrasound.     

Analysis of Ultrasound Propagation in a Metal Rod by Using Finite Element Method

A metal rod is used in the high temperature testing for ultrasonic propagation and heat output,but the trailing echoes generated by ultrasonic penetration through the metal rod seriously affect the recognition and extraction of characteristic signals.According to the phenomenon,the Finite Element Method(FEM)is used to analyze ultrasonic penetration through a metal rod,the reason of the trailing echoes and the regularity of ultrasonic signals.The motion equation of ultrasonic propagation in a metal rod is established and calculated,then the simulation signals and instantaneous cartographies of the process are obtained.Based on the results of the analysis,it can be concluded that the intervals of the trailing echoes are determined by the rod’s diameter and wave velocity.In practical applications,the FEM is used to analyze ultrasonic propagation in the designed buffer rod at first.Based on the characteristics of the simulation signals,the material and dimension are adjusted and selected,aiming to identify the characteristic echo and trailing echoes in time domain and extract characteristic echo from the ultrasonic signals available.     

金属材料小缺陷超声反射信号建模及识别

为了能从含噪声金属材料超声检测信号中有效识别出微小缺陷回波,建立了金属材料超声反射信号模型并提出了基于相关系数的微小缺陷回波识别方法。对含微小缺陷金属材料超声脉冲反射信号的成分进行分析,建立了基于散射声场与高斯回波理论的优化超声回波模型。设计了超声缺陷回波位置识别方法。该方法对超声脉冲反射信号去噪后,取探头发射脉冲信号为参考信号;然后与去噪后的信号逐段求解相关系数;最后对该相关系数序列进行阈值化处理,获得缺陷回波在超声回波信号中的位置。将利用上述优化超声回波模型生成的超声反射信号及其频谱与实验获得的金属材料超声反射信号及其频谱进行了对比,结果表明:两者的时频域特征具有一致性。当将阈值设定为相关系数序列最大值的60%时,能够有效从超声背散射信号中识别出金属材料微小缺陷回波。     

超声导波在H型钢结构损伤识别中的应用

针对H型钢在损伤情况下对超声导波的影响,提出基于超声导波的结构健康监测方法,并探讨了应用超声导波检测技术在H型钢中对结构损伤识别的可行性及其识别能力。采用中心频率为87.5kHz的波形为汉宁窗调幅3.5个周期正弦曲线作为激励波形,应用商业有限元软件ABAQUS对导波在H型钢构件中的传播进行了仿真,同时对无损伤以及有损伤的仿真模型进行实验验证。实验中利用压电材料锆钛酸铝(piezoelectric lead zirconate titanate,简称PZT)换能器来激发和接收在H型钢中传播的导波信号,借助于Morlet小波时频分析等方法对仿真和实验采集到的信号进行处理,并比较实验结果与仿真结果的吻合度。最后分析H型钢中损伤的大小等因素对损伤识别的影响,以及超声导波在H型钢中的损伤识别能力。     

Analyzing the Development of Rail Defects Based on Results of Multichannel Periodic Testing

Russian Journal of Nondestructive Testing - Systems for nondestructive testing (NDT) of rails are multichannel and concurrently use several methods, including ultrasonic, magnetic flux leakage...     

Ultrasonic testing of complexly structured cast-iron articles using a multifunctional software-hardware measuring system

Problems of ultrasonic noise-immune testing of complexly structured cast-iron articles are considered. It is shown that the extraction of informative echo signals from noise and interference requires, in addition to the fulfillment of optimal signal-filtering conditions, the use of flexible multifunctional equipment for ultrasonic testing that allows formation of various signals, flexible variation of their parameters, and application of numerous radio-engineering operations to signals for adapting the parameters of the instrumentation to the characteristics of a tested object.     

Ultrasonic Flaw Detection: Adjustment and Calibration of Equipment Using Samples with Cylindrical Drilling

Questions related to adjusting an ultrasonic flaw detector using cylindrical bores in reference and tuning samples are considered with allowance for the specific features of single- and double-crystal testing schemes, including when a bore is sonified perpendicularly and at an angle to its axis. Requirements have been determined in each scheme to the drilling diameter and the duration of ultrasonic pulses such that signals specularly reflected from the drilling surface not be distorted by creeping and other signals diffracted by the cylinder. It is indicated that under these conditions, cylindrical drilling can be used not only for adjusting the “flaw detector–transducer” system, but also for calibrating the time scan, verifying the accuracy of the depth gage, and checking the flaw-detector attenuator. This approach makes it possible to simplify the construction of measures and tuning samples by eliminating excess reflectors. Examples are given in the echo and TOFD techniques for testing welded joints using traditional and special double-crystal schemes with different probes orientations.     

三点接续式大尺寸工件直线度动态测量方法研究

讨论大尺寸导轨直线度的动态测量方法。首先介绍了三点接续式测量方案的基本原理及数据处理方法。文章结合电梯T型导轨的侧导向面和上导向面的特点,分别选择涡流传感器和平行激光—线阵CCD传感器,作为直线度动态测量的实现方案。最后,对三点接续式方法的测量误差进行了分析。     

Ultrasonic testing of railheads using the electromagnetic-acoustic method

Theoretical and experimental studies of the mirror-shadow ultrasonic testing of railheads using the electromagnetic-acoustic (EMA) method have been performed, and schemes and facilities for this technique have been developed. The main factors affecting the results of tests are determined. The tolerable limits of the changes in the tested parameters are established. It has been shown experimentally that the EMA method is highly sensitive in detecting flaws of technological origin in the railhead bulk, which do not produce echo signals with sufficiently high amplitudes.Translated from Defektoskopiya, Vol. 40, No. 7, 2004, pp. 17–25.Original Russian Text Copyright © 2004 by Sebko, Suchkov, Malakhov     

Features of applying complexly modulated signals in ultrasonic flaw detection

The use of complexly modulated signals during ultrasonic testing of articles with high integral ultrasonic attenuation is substantiated. On the basis of concepts of the optimal-filtering theory, phase-manipulated and frequency-modulated signals most suitable for ultrasonic testing are chosen and the main characteristics of various complexly modulated signals are analyzed. The advantage of using phase-manipulated and frequency-modulated signals in ultrasonic flaw detection for ensuring a high testing resolution and a high sensitivity is shown. It has been revealed that the application of state-of-the-art circuitry components allows the use of various properties of complexly modulated signals and creation of new ultrasonic methods and devices on this basis.     

基于MasterCAM X的型芯零件仿真加工应用

论述了在MasterCAM X环境下,完成型芯零件的外形3D设计、数控仿真加工以及自动生成加工程序NC代码,通过型芯零件的设计和加工,重点讨论了零件仿真加工一般的方法、步骤和应用。     

Metrological and reliability features of a sonic nozzle prover system (SNPS)

Mainly for economic reasons, gas distribution companies have started to use temperature compensated household gas meters. The calibration process of these temperature compensated meters has become more efficient but at the same time the metrological features have remained the same or have even been improved using sonic nozzles as the calibration standards. Repeated test results based on a couple of pre-test processes focus on the sonic nozzle proving method where the shape of the sonic nozzle is according to ISO 9300. The effect of temperature changes on the various temperature compensators was tested. The official testing process for this Sonic Nozzle Prover System is continuing.     

Dynamic Correction of Sensitivity of Flaw Detection Channels in High-Speed Rail Inspection

Russian Journal of Nondestructive Testing - An increase in the reliability of high-speed ultrasonic testing of elongated objects, in particular, railroad rails, is considered. It is shown that the...     

Sonic velocity measurement in molten Pb–Li (16) at high temperature for ultrasonic flowmeter applications

An ultrasonic flowmeter can be a good alternate to electromagnetic flowmeter, being used extensively for high temperature liquid metals. It has an advantage of using it at any location and at any point of time. However, the usage of ultrasonic techniques in high temperature liquid metals is not well established, especially in molten Pb–Li. Pb–Li is considered as a potential coolant candidate in fusion reactor. To study the applicability of ultrasonic techniques in Pb–Li medium with a future scope to develop an ultrasonic flowmeter, a high temperature experimental facility was developed. Sonic velocity was measured in Pb–Li at temperatures ranging from 285 °C to 375 °C using the pulse echo method. It was observed that ultrasonic waves get highly attenuated in molten Pb–Li medium. Out of various tested ways, introduction of W reflector plate could provide detectable reflected signal. The proof of principle test was carried out on few liquids with known values of sonic velocity. The measured sonic velocities have a deviation of ∼6% from that of the reported values.     

基于FastICA的超声A波信号降噪研究

为便于缺陷可视化和提高缺陷定量分析精度,必须降低超声检测过程中多种未知噪声源对超声A波信号的干扰。首先将超声A波信号进行相空间重构,得到一个相空间重构矩阵;然后进行基于FastICA算法的独立分量分析;最后从独立分量中提取出所需的超声信号。为了验证降噪效果,将该降噪方法与小波去噪方法进行对比。实验结果表明:该方法与小波去噪方法效果接近,极大地提高了超声信号的信噪比。同时,该方法与小波去噪方法相比具有自适应能力强、简单且易于实现等优点。