储罐底板缺陷漏磁场空间分布特性研究

发布时间：2018-05-31 17:27

本文选题：腐蚀缺陷 + 漏磁检测　；参考：《东北石油大学》2017年硕士论文

【摘要】：储罐在长期的生产运行中,储罐底板极易发生腐蚀,而腐蚀缺陷也是造成储罐底板失效的重要原因之一。储罐底板缺陷特别是下表面缺陷不易检测,容易发生漏检,造成储罐的腐蚀穿孔,威胁到生产和生命安全,发生严重事故。因此,采用准确可靠的检测方法进行储罐底板的检测和评价,对安全生产有着非常重要的意义。漏磁检测方法以其扫描效率高、检测结果准确等优势被广泛的应用于储罐底板缺陷的检测工作中。目前漏磁检测方法对于储罐底板缺陷的量化一般仅能量化出缺陷的等效长、宽和高,而对于腐蚀缺陷的具体几何形状量化和复杂外形缺陷漏磁场空间分布特性的相关研究较少。迫切需要开展复杂缺陷漏磁场三维空间分布特性和影响因素分析等方面研究工作。本文运用有限元仿真分析的方法建立了各种缺陷的三维有限元模型,对储罐底板复杂外形缺陷漏磁场进行了三维模拟仿真分析。分别针对:缺陷的深度、缺陷的宽度、缺陷的几何形状、缺陷的叠加、缺陷的位置、检测的气隙、钢板的变形、有无垫板以及存在腐蚀产物等情况进行了建模分析。运用控制变量的方法,针对不同的缺陷形式设置了不同条件分别进行模拟,获取缺陷漏磁信号曲线,得到了缺陷参数、缺陷形状、缺陷数量、以及各因素对漏磁场空间分布特性影响的三维仿真结果。在实验室的条件下,选用铁磁性钢板来模拟储罐底板,对应仿真模拟组建了一套储罐底板腐蚀缺陷漏磁检测装置。实验制取了与仿真模拟相对应的不同类型、不同参数缺陷;设置了底板变形、存在腐蚀产物和有无垫板的情况,分别进行相应的储罐底板漏磁检测实验,获取漏磁场空间分布实验结果,得到的实验结果与有限元仿真结果一致。
[Abstract]:It is easy to corrode the bottom plate of the tank in the long run, and the corrosion defect is one of the important reasons for the failure of the bottom plate of the storage tank. The bottom plate defects, especially the bottom surface defects, are difficult to detect and leak, which results in the corrosion and perforation of the tank, which threatens the safety of production and life and causes serious accidents. Therefore, it is very important for safe production to use accurate and reliable detection method to detect and evaluate tank bottom plate. Magnetic flux leakage (MFL) detection method has been widely used in the detection of tank floor defects due to its high scanning efficiency and accurate detection results. There is an urgent need to study the three-dimensional spatial distribution characteristics of complex defect leakage magnetic field and the analysis of influencing factors. In this paper, three dimensional finite element models of various defects are established by using the method of finite element simulation, and the magnetic field leakage of the complex shape defects of the bottom plate of the tank is simulated and analyzed by three dimensional simulation. The depth of the defect, the width of the defect, the geometric shape of the defect, the superposition of the defect, the location of the defect, the detected air gap, the deformation of steel plate, the existence of gasket and the presence of corrosion products are analyzed respectively. By using the method of controlling variable, different conditions are set up for different defect forms to get the signal curve of defect magnetic flux leakage, and the defect parameters, shape and quantity of defect are obtained. The three-dimensional simulation results of the influence of various factors on the spatial distribution of magnetic leakage field are also presented. Under the condition of laboratory, the ferromagnetic plate is used to simulate the bottom plate of the tank, and a set of magnetic flux leakage detection device for corrosion defect of the tank bottom plate is set up corresponding to the simulation. Different types and different parameter defects corresponding to simulation are made in the experiment, and the bottom plate deformation, corrosion products and gasket are set up, and the corresponding magnetic flux leakage detection experiments are carried out respectively. The experimental results of the spatial distribution of the leakage magnetic field are in good agreement with the finite element simulation results.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE988;TG115.284

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