共查询到19条相似文献,搜索用时 125 毫秒
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《仪表技术与传感器》2017,(12)
作为最有潜力替代常规压电传感器的光纤声发射检测方法之一,光纤布拉格光栅(FBG)传感器由于其体积小、抗电磁干扰、易实现分布式检测等特点,已成为国内外研究热点,并出现了商用FBG声发射检测产品。为了更深入地理解FBG传感器的检测效果和应用特性,采用落球实验作为测试用的声发射源,分析了FBG传感系统的声发射信号检测性能,并对比了FBG传感器和压电传感器2种声发射检测系统的时频域响应特性。实验结果表明,信号采样频率范围偏低是制约FBG光纤检测技术在声发射检测上应用的最大障碍。 相似文献
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基于声发射技术的化工容器检测研究 总被引:1,自引:0,他引:1
简述了声发射技术及其在线检测系统的优点,以Z44Y-320型高压截止阀泄漏声发射检测实验为例,介绍了发射技术在化工容器在线检测应用的原理、系统构成和方法步骤。实验结果表明:声发射技术能够及时发现化工容器阀门泄漏。 相似文献
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对气体管道泄漏孔处声源进行了声发射检测试验,分析了气体泄漏产生声发射的原因,通过对不同泄漏孔直径、不同泄漏内压情况下的声发射信号处理与分析,得出气体管道泄漏声源的频率范围及幅度随管道内部压力、泄漏孔径的变化影响规律,并与管道气体泄漏的数值模拟结果进行了对比分析,试验研究结果为气体管道泄漏声发射检测提供依据。 相似文献
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声发射技术在压缩机故障检测中的应用 总被引:3,自引:1,他引:3
研究了声发射传感器在压缩机故障检测中的应用,对声发射检测和振动检测方法的异同进行了分析和比较,介绍了应用于压缩机故障检测的声发射传感器的结构原理,用自行开发的传感器进行了压缩机故障信号的检测分析。 相似文献
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针对声发射信号频散特性导致基于时延估计的气体管道泄漏定位误差大的问题,提出一种基于模态声发射时频分析的泄漏定位方法。该方法采用平滑伪Wigner-Ville时频分布对两泄漏信号的互相关函数进行时频分析,利用互相关函数的时频谱可同时提取泄漏信号的时间延迟和与之对应的频率;然后根据泄漏声发射信号的主导模态的频散曲线即可确定该频率对应的声速,利用实时确定的声速和时间延迟并根据两传感器之间的距离即可确定泄漏点的位置。实验结果表明,采用时频分析的气体管道泄漏定位误差与互相关相比减少了6倍。所提出的模态声发射时频定位方法能有效抑制泄漏信号的频散,提高泄漏信号的相关性,从而更适合用于声发射管道泄漏定位。 相似文献
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《现代制造技术与装备》2016,(7)
锅炉内部结构复杂,使得加压过程中容易因为泄漏问题而导致爆炸。本文从声发射技术概述、锅炉泄漏检测中声发射技术的逐点检测、锅炉泄漏检测中声发射技术的具体应用三个方面进行深入探讨,探究在锅炉泄漏检测中声发射技术的应用问题,并结合具体的现场检测事例,分析声发射技术应用的可行性问题,同时得出一系列相关结论。 相似文献
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《仪表技术与传感器》2016,(12)
为快速准确实现CO_2运输设备的泄漏检测和定位,提出了一种基于声发射的泄漏检测和定位方法。针对管道和储罐两种运输设备的物理特性,分别采用低频和高频声发射传感器采集声波信号,通过时域和频率特征来判断是否发生泄漏;然后为寻找泄漏源,提出了一维和二维定位简化模型,首先使用经验模态分解法(EMD)对泄漏信号进行了多层分解,然后采用到达时间差法(TDOA)和双曲线法进行泄漏源的定位。结果表明:CO_2泄漏信号与未泄漏信号在时域和频率存在明显区别,一维和二维定位模型能够有效地完成CO_2运输管道和储罐的泄漏定位。 相似文献
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This paper presents a relative calibration method for an internal valve leakage rate measurement system using both microcontroller and acoustic emission (AE) methods. An air jet was selected to calibrate because it provides a frequency spectrum similar to the AE spectrum obtained from the valve leak, especially in the frequency range of 100-300 kHz. Three AE sensors mounted on a valve were used to validate the system calibration. Ratios between the average energy (AErms) were obtained from each pair of sensors, and these ratios were used to transfer the leakage AErms value. Subsequence, its performance to predict the leakage rate in the laboratory and in the field was tested. The error is less than 5% in almost cases. Its benefit is to reduce the recalibration time when a part of measurement system is changed. Accordingly, inexpensive equipment including an AE sensor was built, and its system performance was revealed. 相似文献
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基于动态压力信号的管道泄漏检测技术研究 总被引:15,自引:0,他引:15
本文提出基于压电传感器信号特征的管道泄漏检测方法。比较了基于压电传感器和压力传感器的管道泄漏检测的优缺点,介绍了基于压电式动态压力变送器的管道泄漏检测的系统结构、压电式动态压力变送器的外形特征和内部结构,分析了基于压电式动态压力变送器的管道泄漏信号的时、频域特征,给出了相应的检测和定位方法。实际应用表明,这种方法可以快速、准确地进行泄漏检测和定位,并能可靠地工作。 相似文献
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Saman Davoodi Amir Mostafapour 《The International Journal of Advanced Manufacturing Technology》2014,70(5-8):1125-1135
Pipelines leakage in power plant, petrochemical complexes, and refineries can lead to explosion, pollution, and severe physical damages, so precise and on time leak locating is very important. There are many techniques for detecting and locating the leakage. In this research, we represent the leak locating principle in pressurized gas pipelines by using acoustic emission theory. An algorithm for finding the location of continuous acoustic waves resulted from leakage is provided by MATLAB software. The used leak locating technique is a combination of wavelet transform, filtering, and cross-correlation methods. The resulted acoustic emission signals were analyzed into high and low frequencies by wavelet transform and available noises on them were omitted completely by filtering. Then de-noised acoustic emission signals were reconstructed. Time differences of de-noised waves were calculated precisely by using cross-correlation function. For studying the accuracy of used method, acoustic emission testing was done by continuous leakage source. The resulted signals of leakage were recorded by two acoustic sensors in two sides of leakage source, and time difference and leak location were calculated by using the algorithm. Several tests were done by changing sensor distance from leakage source and error percent of less than 3 % was resulted in leak locating that indicated high precision of used algorithm. 相似文献
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To conveniently carry out the pipeline leak experiment in a laboratory, leak acoustic signals are simulated by using the converse
piezoelectric effect of a piezoelectric transducer (PZT) cylindrical phase modulator. On the basis of the piezoelectric equations
and electromechanical equivalence principle, the transfer function of a PZT cylindrical phase modulator is delivered. A PZT
cylindrical phase modulator is designed, and the numerical simulation is conducted. Results prove that the PZT cylindrical
phase modulator can effectively simulate leak acoustic emission signals when the frequency is lower than 25 KHz.
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Translated from Journal of Beijing University of Technology, 2006, 32(8): 683–687 [译自: 北京工业大学学报] 相似文献
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D Choi W. T Kwon C. N Chu 《The International Journal of Advanced Manufacturing Technology》1999,15(5):305-310
The sensor fusion method using both an acoustic emission (AE) sensor and a built-in force sensor is introduced for on-line
tool condition monitoring during turning. The cutting force was measured by a built-in piezoelectric force sensor, which was
inserted in the tool turret housing of an NC lathe. FEM analysis was carried out to locate the most sensitive position for
the sensor. A burst of AE signal was used as a triggering signal to inspect the cutting force. A significant drop in cutting
force indicated tool breakage. The algorithm was implemented in a DSP board and the monitoring system was installed on a CNC
lathe in an FMS line for in-process tool-breakage detection. The proposed system showed an excellent monitoring capability. 相似文献
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According to cold heading process with overloaded craft, high-impact dynamic real-time measurement requirements, this paper presents researches on dynamic characteristics and optimization of PVDF piezoelectric film force sensor for steel ball cold heading forming quality monitoring, through the combination method of mechanism analysis, mathematical modeling, numerical simulation and experimental validation. The motivation and strategic objectives are to breakthrough dynamic time-varying impacting load measuring fundamental technologies in steel ball forging process. The structure of piezoelectric film force sensor is proposed. The theoretical calculation formula of natural frequency is deduced and calculated by using MATLAB software. The mechanical performance analysis on dynamic model and structural optimization simulation by FEM is carried out. In order to study the validity of the proposed method, a prototype of the sensor is fabricated. The static and dynamic calibration devices are designed to realize calibration experiments on the fabricated PVDF piezoelectric film force sensor. The differences among experimental value, simulation value and the theoretical value are given. The nonlinear error of the fabricated sensor is 0.197%. The sensor’s first order natural frequency value is 5238 Hz. It is proved that the PVDF piezoelectric film force sensor has superior dynamic performance and high accuracy for measuring deformation in steel ball. The paper will provide important scientific basis and technical foundation to achieve superior performance steel ball. 相似文献
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集成流体声发射传感器的设计 总被引:1,自引:0,他引:1
本文论述了一种新型流体声发射传感器的集成结构和设计原理,讨论了如何利用声能集中原理提高灵敏度和压电元件形状及边界条件对传感器频率响应的影响等理论问题,最后,对其距离传播特性进行了测试,用大量的实验验证了其实用性和可靠性。 相似文献
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火车的车轮在高速行驶的过程中,由于受到各方面力的作用,可能会产生裂纹,需要对其进行检测。本文从声发射的机理出发,一步步阐述了一种新型的声发射传感器——火车轮裂纹检测传感器设计的原理,同时给出了其中内置的前置放大器的设计原理及结构图。传感器使用固体材料作为传感器的传播介质,用新型的压电材料作为敏感元件,提高了灵敏度。 相似文献
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Joongkuen Lee Jaehwan Kim Chae Cheon Cheong 《Journal of Mechanical Science and Technology》1999,13(6):451-458
The feasibility of piezoelectric smart structures for cabin noise problem is studied numerically and experimentally. A rectangular
enclosure, one side of which is a plate while the other sides are assumed to be rigid, is considered as a cabin. A disk-shaped
piezoelectric sensor and actuator are mounted on the plate structure and the sensor signal is returned to the actuator with
a negative gain. An optimal design of the piezoelectric structure for active noise control of the cabin is performed. The
design variables are the locations and sizes of the disk-shaped piezoelectric actuator and sensor and the actuator gain. To
model the enclosure structure, a finite element method based on a combination of three dimensional piezoelectric, flat shell
and transition elements is used. For the interior acoustic medium, the theoretical solution of a rectangular cavity in the
absence of any elastic structures is used and the coupling effect is included in the finite element equation. The design optimigation
is performed at resonance and off-resonance frequencies, with the results showing a remarkable noise reduction in the cavity.
An experimental verification of the optimally designed configuration confirms the feasibility of piezoelectric smart structures
in resolving cabin noise problems. 相似文献