【作者】 刘延雷；

【导师】 戴光； 马铁伦；

【作者基本信息】 大庆石油学院 ， 化工过程与机械， 2006， 硕士

【摘要】 近年来,漏磁检测方法被广泛应用,尤其在腐蚀坑状缺陷检测的研究和推广应用中,漏磁检测已经逐渐成为比较成熟的检测技术。在储罐和管道服役期间,除了腐蚀缺陷存在外,还可能形成许多危险性大的裂纹缺陷,但是由于裂纹的漏磁检测结果受很多因素的影响,这给裂纹的评价增加了难度。 本文提出了理论模型计算、有限元模拟和实验三种方法对裂纹漏磁场进行分析解决了一系列问题。建立了矩形槽理论模型对裂纹参数(裂纹深度、裂纹宽度、裂纹角度等)进行了分析并得出规律;基于有限元方法分别得出裂纹漏磁场随磁化结构参数(磁铁厚度、极靴间距、气隙高度等)、裂纹参数(裂纹深度、裂纹角度、裂纹宽度及裂纹间距等)变化的规律:通过实验对以上两种方法的部分分析结果进行了验证。由于裂纹漏磁场信号较小,本文还引进了聚磁技术,并通过有限元分析、及实验选择了合理的聚磁结构,并得到了添加聚磁结构后,裂纹漏磁场随裂纹宽度和深度的变化曲线。 通过建立理论模型进行分析和实验模拟得到了一系列结论,结论表明:通过不同裂纹参数的设置能得到裂纹漏磁场随参数变化的影响曲线;合理的选择磁化结构能更好的对被测件进行磁化;聚磁技术可以应用到漏磁检测裂纹上,聚磁装置能提高漏磁检测裂纹的灵敏度。 本文对裂纹漏磁场的分析将为漏磁检测裂纹提供依据。更多还原

【Abstract】 In recent years, the method of MFL is widely used. Especially in the spoiled etch pit shape flaw testing research and the promoted application, magnetic flux leakage testing has already become the mature testing technology. In storage tank and pipeline service period, besides corrosion flaw existence, but also possibly forms many risky cracks flaw. Because the result of magnetic flux leakage testing contains many factors with influence, this increased the difficulty for the crack appraisal.This article proposed the theoretical model computation, the finite element simulation and experiments to carry on the analysis of the crack and solved a series of problems. First was the establishment of the rectangular trough theoretical model of different crack parameters (crack depth, crack width, crack angle and so on) have been analyzed and obtained the rule;Then separately obtained the crack stray field basing on the finite element method along with the magnetization design parameter (including the thickness of magnet, space of pole shoe, air gap and so on) , the rule of the crack parameters(including depth, width, angles, the space between two cracks and so on);Finally has carried on the confirmation through the experiment to above two methods partial analyses result. Because the crack stray field signal is small, this article has introduced the magnetism gathering installment, through the finite element analysis and the experiment has chosen a reasonable structure, and the curve is also obtained.Though establishing the theoretic model and experiments, the conclusion is obtained. By setting different parameters can get the curve of influence;Choosing the magnetism in reason can improve the effect of magnetization;Magnetism gathering technology is applied into Cracks’ flux leakage testing, it can enhance the delicacy of testing.This study which do main on the crack’s flux leakage will provide thereunder for magnetic flux leakage testing of the crack.更多还原