【作者】 宋志东；

【导师】 靳世久；

【作者基本信息】 天津大学 ， 精密仪器及机械， 2006， 硕士

【摘要】 管道运输业在经济建设和国防工业中发挥着越来越重要的作用。维护管道安全运行,防止管道生产事故的发生是管道工业生产和安全管理部门一项很重要的工作。管道泄漏事故一旦发生,不仅造成大量物质损失,更为严重的是有可能带来人身伤亡事故。管道缺陷检测是油气管道安全检测的重要方面。传统常规的检测方法往往费时费事,而超声导波技术由于其具有检测效率高、速度快和检测管壁整个厚度等的优势,使这项技术在长距离快速检测和管道完整性评价等方面受到无损检测领域的广泛关注。本文对超声导波技术应用于工业管道缺陷无损检测进行了理论和实验研究。首先,分析了国内外超声导波无损检测技术研究现状,介绍了超声导波的基本概念和原理;其次,详细推导了空心圆管中的导波理论,得出了空心圆管中柱面导波频散方程,对频散曲线进行了计算,分析了空心圆管中纵波、扭转波、弯曲波三种纵向模态导波;给出了在圆管中激励超声导波的方法,给出管道检测常用的导波模态L(0,2)和T(0,1)的激发方法;分析了管道中超声导波传播特性,包括导波的衰减特性和缺陷反射特性;在理论分析基础上,应用超声导波检测仪对管道缺陷进行检测实验,以轴对称纵向L(0,2)模态和扭转T(0,1)模态导波进行检测,实验结果与理论分析基本吻合。最后,对纵向L(0,2)模态和扭转T(0,1)模态导波检测结果进行分析,表明:纵向模态和扭转模态导波检测到了全部的焊缝等特征,对预制缺陷有回波信号,并可以较为准确的对缺陷定位;导波对周向缺陷较为敏感,证明了应用超声导波技术对工业管道进行无损检测的可行性;对两种模态的检测结果进行对比分析,前者的波形明显比后者复杂得多,表明纵向导波对所激发信号的轴对称性要求更高。更多还原

【Abstract】 Pipeline transportation business plays a much important role in the economy construction and national defence industry. Keeping pipeline safety and preventing pipeline accidents is an important work to the pipeline industry and safety management bureau. If pipeline leakage happens, lots of money would lost, more seriously it maybe causes casualty. Pipeline defects detection is a main work of safety inspection for oil or gas pipeline. Conventional inspection methods always take time and take a lot of trouble, meanwhile ultrasonic guided waves techniqhe has good command of efficiency and it can inspects the whole wall thickness of pipe. Therefore, as an NDT method, ultrasonic guided wave technique is paid more attention in pipeline long-rapid testing and plant integrity management area.In this paper, industry pipeline defects NDT using ultrasonic guided waves was carried out theoretically and experimentally. Firstly, some main studies and progresses in this field were reviewed, and the relative theoretical basis was introduced. Secondly, the theories of guided wave in hollow circular cylinder were deduced in details. The characteristic equation of cylindrical guided wave was obtained and the corresponding dispersion curves were calculated. And three cylindrical guided wave modes in hollow circular cylinder were analyzed, including longitude, torsional and flexural mode. Then excitation method in hollow cylinder was given and also the usual testing modes L(0,2) and T(0,1) excitation. The propagation characteristics in cylinders were analyzed, including attenuation and reflection. On the basis of theoretical analysis, pipeline defects detection experiments using guided wave testing instrument was done, and the results are greatly agreed with the theoretical analysis. Finally, the L(0,2) mode and T(0,1) mode testing results were analyzed, it indicates that the longitude mode and torsional mode detected all of the welds and the prefab defects, and the positions were localized; guided wave is more sensitive to circumferential defects; comparing the results of the two modes, we know the waveforms of the former were obviously complicated than the latter’s, that indicates longitude guided wave calls for more accurate axisymmetric excitation signals.更多还原