共查询到18条相似文献,搜索用时 171 毫秒
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光纤传感技术及其在管道监测中的应用 总被引:1,自引:0,他引:1
管道安全关系到人类生命和财产安全,及时掌握管道结构健康状态是确保其安全运行的重要前提,近年来发展起来的光纤传感技术为管道结构的安全监测提供了技术保障。传感器的选择和使用是进行结构监测时首先考虑的问题,重点介绍了SOFO点式、FBG准分布式、BOTDR和BOTDA分布式光纤传感器等光纤传感技术的系统组成、基本原理及关键技术,对其性能和特点进行了对比分析;在此基础上,探讨了适用于管道变形监测的FBG和BOTDA光纤监测实用系统,及适用于管道泄漏监测的基于拉曼散射的OTDR分布式温度传感技术和基于模态分布调制干涉技术的油气管道检测系统。分析了其各自作为结构监测传感器的优缺点,为今后的管道监测选用提供了依据。 相似文献
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针对岩石破裂声发射检测中的常规检测仪器抗电磁干扰差、灵敏度低、可靠性差等不足,提出采用光纤光栅传感技术来实现声发射检测,分析了光纤光栅传感检测应变和声发射的机理,组建了相应的声发射检测模拟实验系统,给出了模拟实验的500kHz激励声信号和光纤光栅传感响应信号。利用软件RFPA进行了岩石破裂的数值模拟,选择水泥河砂作为主要原料的砂浆材料,制作了类岩石材料实验试件,并在单轴数控压力机上进行了岩石试件加载破裂声发射实验,用光纤光栅传感器来探测和记录声发射能量及声发射累计次数,证明该传感器能实现声发射检测。 相似文献
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气体管道泄漏检测技术探讨 总被引:1,自引:0,他引:1
介绍了现代气体管道泄漏检测诊断技术,对现有气体管道泄漏检测方法从原理、检测精确度与可靠性等多方面进行了分析比较。并针对现有方法的不足提出了改进,认为SCADA系统是今后气体长输管道泄漏检测发展的方向。 相似文献
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针对船舶管系频繁的调泵、调阀等常规操作极易引发泄漏检测系统误报警这一问题,采用适于小样本数据集处理的支持向量机( SVM)从管系多种工况中识别泄漏。使用具备局部和全局最优解搜索能力的人工蜂群算法( ABC)优化SVM参数,避免陷入局部最优解,提高识别正确率。通过小波分析提取工况特征向量,设计和组建人工蜂群优化支持向量机( ABC?SVM)分类器,实现了泄漏识别。与BP神经网络等常用算法比较, ABC?SVM算法具有更高的泄漏识别正确率和适应性。 相似文献
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A reference standard for the development of acoustic emission pipeline leak detection techniques 总被引:1,自引:0,他引:1
R. K. Miller A. A. Pollock D. J. Watts J. M. Carlyle A. N. Tafuri J. J. YezziJr 《NDT & E International》1999,32(1):2448
A reference standard was constructed for setting up and evaluating AE equipment to be used in pipeline leak detection. The reference standard comprises a short length of 2-inch diameter piping with facilities for introducing several kinds of controlled leaks. The reference standard proved very valuable not only for checking out equipment, but also for characterizing source mechanisms as part of an integrated approach to quantitative AE leak detection/location technology. The effects of pressure and air injection were measured for thread leaks on the order of 0.1 gal h−1, a leakage rate that is important in the context of environmental protection regulations. Taking this knowledge to the field, a thread leak of only 0.014 gal h−1 was successfully detected and located by injecting nitrogen into the line at 25 psi. This leak was located with 1 foot accuracy, using two different location techniques and 25-foot sensor spacing. It is envisioned that in the future, AE inspectors in the field will make systematic use of several two-phase flow processes and soil enhancement mechanisms that are being characterized by means of this new reference standard. 相似文献
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Thermal stress cleaving is a prospective technique for separating a wafer or thin plate from brittle materials such as glasses and ceramics. In this paper, the cleaving mechanism of a silicon wafer irradiated with Nd: YAG laser is investigated. A pulsed laser is used for the purpose of investigating the mechanism of crack propagation more precisely. The temperature at the area irradiated with the laser is measured using a two-color pyrometer with an optical fiber. The AE signal is also measured to examine the mechanism of the crack propagation. The AE signal makes it possible to monitor the crack behaviour. During one pulse of the laser, crack propagation begins some milliseconds after laser heating and ceases at about the end of irradiation. The temperature at the area irradiated with the laser is an important factor in the control of the propagation of the crack to achieve high cleaving accuracy and low thermal damage. 相似文献
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A new type of pyrometer is developed, in which two optical fibers are used to accept and transmit the infrared energy. These two fibers are connected using a non-contact fiber coupler. In turning, the incidence face of one optical fiber which is embedded in a rotating workpiece accepts the infrared rays radiated from the cutting tool and emits it at the other face. The infrared energy is accepted by the other optical fiber which is fixed at the pyrometer and led to the two-color detector. In endmilling, the temperature history of CBN tool face during cutting is measured, where the fiber is embedded in the endmill. 相似文献