In order to study the ability of terahertz nondestructive testing technology to detect the bonding defects of multilayer heat-resistant structures, artificial defects were preset in the two-layer adhesive of composite material-adhesive-composite material-adhesive-metal bonding structure, and pulsed The Hertz wave imaging method detects the samples.The results show that the terahertz time-domain signal can be obtained after the terahertz wave penetrates the bonding structure of the multilayer heat-resistant composite material, and the defect images of different adhesive layers are obtained after the characteristic waveband data processing.It can clearly image the 0.15mm air layer and 0.15mm metal plate in the sizing layer between the heat-resistant composite material and the breathable composite material, and the imaging can distinguish the 0.15mm air layer in the lower rubber layer between the breathable composite material and the metal plate.The research results provide an effective method for the detection and evaluation of the bonding quality of multilayer heat-resistant composite materials.
Industrial pipeline is often used in petrochemical industry, which is a kind of common pressure special equipment in various chemical installations.Different from boilers and pressure vessels, industrial pipelines are very difficult to manage due to the large number of overhead laying and complex installation forms, and industrial pipelines are often in very bad working conditions, so the accident probability caused by corrosion leakage of industrial pipelines is higher than that of other pressure special equipment. There are many methods for the corrosion detection of industrial pipelines.Pulsed eddy current testing technology is one of the new non-destructive testing technology vigorously promoted in recent years.It has the advantage of realizing online detection without removing the insulation/cold protection layer.Through the actual testing cases, it is proved that the pulsed eddy current testing technology has a very good detection ability for industrial pipeline corrosion defects, which is worthy of further promotion.
The Phased Array Ultrasonic Testing（PAUT） and Digital Radiographic（DR） Testing were proposed to detect the Electro-Fusion Joints of polyethylene pipes with different welding defects, and analyzed the characteristic maps of different welding defects, then summarized the advantages and disadvantages of PAUT and DR in detecting electro-fusion welding defects of polyethylene pipeline.The test results showed that, the PAUT method had a high detection rate for process defects（cold and over welding）,slag inclusion, holes and incomplete fusion, especially to the process defects in different degrees, this method had a high detection sensitivity, but it was difficult to characterize holes, slag inclusion and incomplete fusion defects.DR method had a high defect detection rate for holes, slag inclusion, incomplete fusion and over welding defects, and the detection results were intuitive and reliable, but the detection rate for cold welding defects was low.
Aiming at the problem of effective identification of micro-defect on the surface and deep layers of the tab welding seam of aviation lithium battery, a magnetic eddy current detection method based on the combination of high-current and wide-area uniform eddy current field and high-sensitivity gradient differential coil is proposed.This paper systematically expounds the high-sensitivity detection mechanism of the gradient differential coil and its influencing factors.Based on the excitation coil wound by litz wire, a uniform eddy current excitation field is applied to the entire surface of the electrode plate, and the gradient differential coil array is used to pick up the induced eddy current signal.Accordingly, the tab welding seam micro-defect detection system is established.The research results show that the magnetic eddy current detection technology can be used to compare and analyze the difference between the eddy current field of the tab welding seam and the normal area, so as to accurately obtain the characteristic parameters such as the size and location of micro-defect in the tab welding seam, which could further improve the detection image reconstruction function.This method has great engineering value for ensuring the safe and stable operation of the aviation lithium batteries.
In order to study the performance of Q345R material under cyclic loading, fatigue crack propagation experiments were carried out at different frequencies.Acoustic emission signal characteristic parameters were extracted and comprehensively analyzed by comparing the damage process in the fatigue loading process.It is found that the relationship between the fatigue crack growth length and the number of cycles is different at different loading frequencies.At the same time, acoustic emission（AE） was used to monitor the characteristic parameters in the process of fatigue crack propagation and fracture, which provided a reference for the application of AE technology in the online detection of Q345R materials.
This paper comprehensively introduces the application degree of PAUT and TOFD in the welds detection of pressure parts of boiler and pressure vessel.Compared with other conventional volume NDT methods, it highlights the long-term advantages of saving money, saving time and excellent detectability.
信息化是目前多数制造型企业生产发展的主导方向之一,X射线无损检测作为制造型企业生产过程中重要的质量检测手段,其设备的信息化功能要符合企业信息化发展的需求.本文对生产过程中X射线无损检测系统的信息化需求进行分析,以数据库中间表和webservice为例探讨与企业信息管理系统的对接方法,最后对笔者公司研制的全自动X射线轮胎检测系统的信息化应用情况进行说明.
Aiming at the internal leakage problem of liquid pipeline valves, the DN25 liquid pipeline ball valve was taken as the research object to conduct a comprehensive study of numerical simulation and experiment.Firstly, the distribution laws of internal leakage flow field and sound field under the fixed opening of liquid pipeline valve and the fixed inlet pressure are obtained by Fluent simulation.Secondly, an experimental platform for valve internal leakage of liquid pipeline is built to verify the simulation law.The sample data of internal leakage are collected based on the acoustic emission system, and the signal strength of internal leakage sound source is characterized by two characteristic parameters of acoustic emission signal, namely mean square root value and energy counting, and the relationship between characteristic parameters and pressure and opening degree is obtained.The concentrated distribution range of frequency domain peak.In the comparison of experimental and simulation results, the variation trend of internal leakage rate and sound intensity distribution are generally consistent, and the average percentage error of internal leakage rate is less than 10%,which confirms the effectiveness of internal leakage simulation.
采用图像模块,采集机器人行驶路径上的焊缝图像数据,通过无线网络将图像数据传至上位机,上位机系统利用图像处理算法,提取图像中的焊缝,进一步生成机器人行走控制命令,控制机器人对行驶路径进行修正,达到跟随焊缝的效果.实验结果表明,该系统能对行驶路径上的焊缝进行实时识别和跟随,当爬壁机器人初始位置与焊缝位置偏差较大时,仍然能自我修正行驶方向,使得爬壁机器人行驶方向与焊缝位置重合.
Through analyzing the difficult problems in the process of X-ray detection of the girth weld of the welding butt of the small and medium diameter conduit of aluminum alloy or stainless steel commonly used in aerospace, the corresponding solutions and optimization schemes are formulated through the process test research, so as to improve the reliability and efficiency of detection, and provide certain reference guidance for the X-ray detection of the girth weld of the welding butt of the small and medium diameter conduit.
With the continuous development of ultrasonic imaging technology, the algorithm of ultrasonic A-scan signal processing to B-scan signal is also constantly updated and improved.Ultrasonic Total Focus Method（TFM）imaging algorithm is based on Full Matrix Capture（FMC） for signal processing, which can focus all areas of the test piece.In this paper, COMSOL Multiphysics software is used to model the transverse hole defects in metal aluminum plate, and FMC method is used for signal acquisition.Combined with MATLAB software, the collected data are processed by TFM algorithm to obtain defect B-scan information.At the same time, the Half Focus Method（ HFM） is compared and studied.Under the ideal state of simulation, the B-scan imaging results of the two algorithms are superimposed by different cross-section simulation maps to achieve the three-dimensional defect inversion effect.The defect simulation results of TFM and HFM are compared.The results show that the TFM imaging technology can accurately reflect the position and shape information of the defect.Although the HFM algorithm can save nearly half of the data processing time and realize the ultrasonic imaging of the defect faster, the imaging results are slightly worse than those of the TFM algorithm.At the same time, the combination of COMSOL Multiphysics and MATLAB can better realize the simulation of ultrasonic nondestructive testing.
采用全数据采集的方法进行自动化相控阵成像检测，可以保留检测过程中的关键信息，实现数据后处理及多类型成像，有利于复杂结构零件的质量评估。但是相控阵超声检测为多通道数据并行采集模式，数据量大、数据处理时间长也成为制约该方法工程化应用的瓶颈。本文介绍一种基于ALOK算法进行数据采集、压缩的方法，采用基于该算法的检测系统对复合材料三层板板粘接结构试样进行检测，实现了自动化相控阵超声成像检测及全数据采集。基于采集的超声信号，可以实现被检试样的A、B、C型显示、任意位置A扫描波形回放，以及更改闸门设置生成不同图像的功能，对复杂结构零件的内部质量评估有积极作用。
通过冷阴极数字射线成像与常规射线检测对比试验,证明了该技术的可靠性和辐射防护风险控制的优越性,是理想的射线检测方法.同时开展了冷阴极数字射线成像技术在其他应用场景的初步研究.
由于核电站BOSS焊缝结构的特殊性和胶片照相技术的局限性,尝试使用X射线数字成像的工艺和设备对BOSS焊缝进行检验.通过试验确定核电站BOSS焊缝数字射线检测最佳工艺参数,为核电站役前和在役射线检测提供技术支持.
为了验证碳纤维树脂基复合材料超声检测的有效性和准确性,对铺层树脂传递模塑成型(RTM)复合材料超声检测中典型的缺陷信号进行了解剖,并采用微焦点CT检测和金相表征分析,发现超声检测对于分层和裂纹类缺陷敏感,但无法进一步对二者进行分辨;对于密集孔隙和微裂纹也可以很好检出,却也无法进一步分辨;对于微裂纹,微焦点CT无法检出,而超声检测可检出.
针对近几年来国内外关于激光焊缝无损检测技术的研究工作进行了详细分析与研究,比较了激光焊缝各类无损检测方法的优劣性,并对未来激光焊缝质量检测技术发展方向进行了探讨.
分析比较了美国机械工程师协会锅炉压力容器规范与核电厂核岛机械设备无损检测标准(NB/T20003.2标准)相关规范中超声焊缝检测部分内容,为核电标准国产化后NB/T20003.2标准的运用及有关单位和检验人员更加深入地理解和正确执行标准提供参考、讨论.
探伤是保证铁路安全的重要手段,特别是高原高海拔地区,昼夜温差大,更容易发生由于钢轨内部伤损引起的断裂事故.双轨式钢轨探伤仪是一种新型高效的钢轨探伤设备并获得了广泛应用,但是在高原高海拔地区的应用研究却很缺乏.从机械、电子、探轮等方面研究高原高海拔地区的气候对双轨式钢轨超声波探伤仪的影响并提出解决方案,设计了一款高原型双轨式钢轨超声波探伤仪,其能够取代现有的手推式钢轨超声波探伤仪进行探伤作业,从而改变了高原高海拔地区的钢轨探伤作业模式.
根据蒸汽发生器胀接工艺和设计要求,分析了胀接区的质量检测要求,使用涡流轮廓检测法实现对胀接区的质量检测和常见缺陷分析,并介绍了2种辅助检测方法:内径变化测量法和解剖法.3种方法的组合使用,可以实现对蒸汽发生器传热管胀接过程的质量控制.
