架空管道漏磁外检测系统的研制及应用

发布时间：2018-04-02 05:25

本文选题：架空管道　切入点：无损检测　出处：《华中科技大学》2015年硕士论文

【摘要】：漏磁检测具有非接触、速度快、效率高等优点,成为近年来广泛使用的一种检测方法。本学位论文,针对架空管道(Φ57~Φ219 mm)规格多、工况复杂等给漏磁检测带来的工程难题展开研究,研制出管道漏磁外检测系统,并开展现场应用。首先,在对架空管道的检测工况进行详细分析的基础上,确定漏磁检测用可重构磁化方案;结合磁化器的设计计算,给出一套架空管道漏磁外检测系统总体方案。设计计算磁化器时,利用有限元方法建立架空管道三维漏磁检测模型,通过将存在通孔缺陷的磁场信号与无缺陷的磁场信号求差,获得了真实漏磁场信号,并通过存在通孔缺陷的磁场信号与无缺陷的磁场信号的比值,获得漏磁检测信号的信噪比。分析磁化器各个几何参数对架空管道内部磁场和缺陷漏磁场的影响,得到漏磁场随磁化器几何尺寸的变化规律,计算得到最优磁化器尺寸;通过对磁化器数量的仿真计算,得到检测不同规格管道所需的最优磁化器数目;并最终确定架空管道漏磁检测系统总体方案。其次,基于磁场计算结果,完成了架空管道漏磁外检测系统的设计与研制。该系统主要由自动爬行器、检测探头、信号无线处理单元和直流电机无线运动控制单元组成。基于电机驱动的爬行方式,可克服已有检测装置中手动方式劳动强度大的不足;检测探头采用刚性与柔性结构相结合的方式,保证检测信号稳定;基于2.4GHz Hz无线遥控技术的运动控制单元及采用WI-FI的信号处理单元,实现检测信号和远程遥控信号的无线传输,取代现有的有线电缆传输方式,提高操作的简便性,扩大仪器的适用范围。最后,根据无损检测要求,研究设计了包含通孔、刻槽、内外盲孔系列的漏磁检测试件,利用所研制的检测系统对其进行了系统测试,获取不同试件的漏磁检测信号特性,在此基础上,进一步开展了现场应用试验。结果表明所研制的检测系统现场适应性好,操作方便,检测效率高,信号稳定。本学位论文的研究工作为国家标准《GB/T 31212-2014无损检测漏磁检测总则》的制订提供了部分支撑。
[Abstract]:Magnetic flux leakage (MFL) detection has the advantages of non-contact, high speed and high efficiency, so it has been widely used in recent years. In this dissertation, there are many specifications for overhead pipelines (桅 57 ~ 桅 219mm). The complex working conditions and other engineering problems brought about by magnetic flux leakage detection are studied, and a pipeline magnetic flux leakage detection system is developed and applied in the field. Firstly, on the basis of detailed analysis of the detection conditions of overhead pipelines, The reconfigurable magnetization scheme for magnetic leakage detection is determined, and a set of overall scheme of external magnetic leakage detection system for overhead pipeline is given in combination with the design and calculation of magnetizer. When the magnetizer is designed and calculated, the three-dimensional magnetic leakage detection model of overhead pipeline is established by using finite element method. Through the difference between the magnetic field signal with through hole defect and the magnetic field signal without defect, the true magnetic field leakage signal is obtained, and the ratio of the magnetic field signal with through hole defect to that without defect is obtained. The signal-to-noise ratio (SNR) of magnetic flux leakage detection signal is obtained. The influence of each geometry parameter of magnetizer on the magnetic field and defect magnetic field in overhead pipeline is analyzed. The variation rule of leakage magnetic field with the geometry size of magnetizer is obtained, and the optimum magnetizer size is calculated. Through the simulation calculation of the number of magnetizers, the optimal number of magnetizers needed to detect the pipeline of different specifications is obtained, and the overall scheme of the magnetic leakage detection system of the overhead pipeline is finally determined. Secondly, based on the results of the magnetic field calculation, The design and development of an external magnetic flux leakage detection system for overhead pipeline is completed. The system is mainly composed of automatic crawler, detection probe, wireless signal processing unit and wireless motion control unit of DC motor. It can overcome the shortage of manual labor intensity in the existing detection devices, the detection probe adopts the combination of rigid and flexible structure to ensure the stability of the detection signal. The motion control unit based on 2.4GHz Hz wireless remote control technology and the signal processing unit using WI-FI can realize the wireless transmission of detection signal and remote control signal, replace the existing cable transmission mode, and improve the simplicity of operation. Finally, according to the requirements of nondestructive testing, the magnetic flux leakage testing samples including through hole, groove, inside and outside blind hole series are designed and tested systematically by using the developed testing system. On the basis of obtaining the characteristics of magnetic flux leakage detection signal of different samples, the field application test is carried out further. The results show that the developed detection system has good field adaptability, convenient operation and high detection efficiency. The research work of this dissertation provides some support for the formulation of the National Standard < GB/T 31212-2014 General principles of Magnetic Flux leakage Detection for NDT.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U178

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