基于复合励磁方法的漏磁检测仿真分析与实验研究

发布时间：2019-06-21 18:40

【摘要】：随着无损检测技术的发展,漏磁检测技术应用到了越来越多的领域。本文依据漏磁检测原理,将原木应用于电机技术的复合励磁方法引入漏磁检测领域,采用电磁励磁与永磁励磁相结合的磁化结构,通过调节电流,控制励磁磁场的强弱,以使复合励磁漏磁检测仪可以根据不同厚度储罐底板调节励磁场强度,相比永磁漏磁检测仪器减轻了检测人员劳动强度。木文分析了复合励磁漏磁检测的原理,提出了复合励磁漏磁检测的方法。建立了串联复合励磁结构模型、单路并联复合励磁结构模型和多路并联复合励磁结构模型,以及更换导磁材料后的复合励磁结构模型等共五种模型,并对五种模型分别进行模拟仿真,得出五种复合励磁模型下的漏磁场空间分布特性。采用控制变量法,应用ANSYS有限元软件对五种模型分别在不同缺陷形状、缺陷深度、缺陷宽度、试板厚度、安匝数情况下的进行对比分析。根据仿真计算结果,得到了相应的缺陷漏磁场特征。在五种模型漏磁场磁通量密度水平分量Bx中,由硅钢材质组成衔铁的单路并联结构模型产生的磁通量密度水平分量Bx最强,其次是串联复合励结构磁模型,再次是由硅钢衔铁组成的多路并联结构模型,单路并联励磁结构模型与多路并联励磁结构模型产生的磁通量密度水平分量Bx是最小的,且两者峰值几乎一样。研制了复合励磁漏磁检测系统。该系统具有四种励磁结构,分别是串联复合励磁结构、多路并联复合励磁结构、硅钢衔铁单路并联复合励磁结构和硅钢衔铁多路并联复合励磁结构。在实验室条件下应用所研制的复合励磁漏磁检测仪进行了大量的实验,实验结果表明复合励磁法通过电流的增减,可以实现励磁场强弱的控制。在同样条件下,其励磁效果要比单一励磁方式所产生的磁化强度要强。根据仿真计算结果和实验结果优选出了硅钢单路并联结构作为复合励磁的磁化结构。该结构可以实现15mm板厚20%璧减缺陷的检出。将复合励磁漏磁检测仪的实验数据与皮尔逊积矩相关系数相结合,建立了复合励磁漏磁检测缺陷预测模型,实现了圆柱型缺陷深度参数的预测分析,预测分析结果与实际缺陷的误差小于3%,理论数值与实验数值的相关度大于0.92。
[Abstract]:With the development of nondestructive testing technology, magnetic flux leakage testing technology has been applied to more and more fields. According to the principle of magnetic flux leakage detection, the composite excitation method of log technology is introduced into the field of magnetic leakage detection. The magnetization structure of electromagnetic excitation and permanent magnet excitation is adopted to control the intensity of excitation magnetic field by adjusting the current, so that the compound excitation magnetic leakage detector can adjust the excitation magnetic field intensity according to the bottom plate of storage tank with different thickness, and the labor intensity of the tester is reduced compared with the permanent magnet magnetic flux leakage detection instrument. In this paper, the principle of compound excitation leakage detection is analyzed, and the method of compound excitation leakage detection is put forward. Five kinds of models, such as series compound excitation structure model, single parallel compound excitation structure model and multi-channel parallel compound excitation structure model, as well as the composite excitation structure model after replacing magnetic conductive materials, are established. The five models are simulated respectively, and the spatial distribution characteristics of leakage magnetic field under five kinds of compound excitation models are obtained. The control variable method and ANSYS finite element software are used to compare and analyze the five models under different defect shape, defect depth, defect width, test plate thickness and ampere turn number. According to the simulation results, the corresponding magnetic leakage field characteristics of defects are obtained. Among the five models of magnetic flux density horizontal component Bx, the horizontal magnetic flux density Bx produced by the single channel parallel structure model composed of silicon steel is the strongest, followed by the series composite excitation structure magnetic model, the third is the multi-channel parallel structure model composed of silicon steel armature, and the magnetic flux density horizontal component Bx produced by the single parallel excitation structure model and the multi-channel parallel excitation structure model is the smallest. And the peaks are almost the same. A compound excitation magnetic flux leakage detection system is developed. The system has four kinds of excitation structures, which are series composite excitation structure, multi-channel parallel compound excitation structure, silicon steel armature single parallel compound excitation structure and silicon steel armature multi-channel parallel compound excitation structure. A large number of experiments have been carried out by using the composite excitation leakage detector under laboratory conditions. the experimental results show that the compound excitation method can control the intensity of the excitation field by increasing or decreasing the current. Under the same conditions, the excitation effect is stronger than that produced by a single excitation mode. According to the simulation results and experimental results, the single parallel structure of silicon steel is selected as the magnetization structure of composite excitation. This structure can detect 20% defect of 15mm plate thickness. Combining the experimental data of compound excitation magnetic leakage detector with Pearson product moment correlation coefficient, a prediction model for defect detection of composite excitation magnetic flux leakage detection is established, and the prediction and analysis of cylindrical defect depth parameters are realized. the error between the prediction analysis results and the actual defects is less than 3%, and the correlation between the theoretical value and the experimental value is more than 0.92.
【学位授予单位】：东北石油大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG115.284

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