The Application of Finite Element Method for the Magnetic Flux Leakage Field of Pipeline
-
摘要: 管道漏磁检测及其缺陷漏磁场的仿真技术研究具有十分重要的意义。在对各种漏磁场计算方法进行比较之后，选择了有限元法作为主要研究工具。叙述了漏磁检测的基本原理，介绍了漏磁管道检测装置的工作原理和基本结构，建立了管道漏磁检测中缺陷漏磁场计算的三维有限元模型，并以此为基础分别研究了缺陷漏磁信号特点、缺陷的几何尺寸与漏磁信号的关系、以及材料壁厚等对漏磁信号的影响等问题。通过对多磁化单元结构进行有限元模拟和试验仿真，发现多个磁化单元会造成磁场的叠加，磁化单元数量的增加会使缺陷处漏磁场增强，并且中间磁化单位的增加量要大于两侧。缺陷的几何尺寸影响漏磁场的分布，在一定缺陷直径范围内，缺陷深度与漏磁场信号强度呈近似线性关系。无论被测管道壁厚如何变化，相同几何参数的缺陷漏磁场轴向分量变化趋势仍然相同。适当选取提离值，将有助于获得良好的漏磁场信号。Abstract: It is very important to take the simulation analysis for the magnetic flux leakage testing both on pipeline and the defects on it. After comparing various magnetic flux leakage calculation methods, the finite element method (FEM) was taken as the analysis method in the research. The theoretical principle of magnetic flux leakage testing, the working mechanism and basic structure of magnetic flux leakage testing equipment were introduced, and also the FEM 3D module of defect magnetic flux leakage field in pipeline was built. Through the FEM and experiments simulation for multi magnetizing units, such conclusions were obtained as below: the magnetic field overlap from multi-magnetizing units will intense the magnetic flux leakage on the top of the defect, and also the number increase of the magnetizing units located at the central of the magnetizer will produce more intensive magnetic field than both side units of the magnetizer. The dimension of the defect will affect the distribution of the magnetic flux leakage filed. In a certain defect diameter size variation, there is a linear relationship between the intensity of the magnetic flux leakage field and the defect depth. No matter how thick the pipeline is, there is a similar varying trend for the axial component of the magnetic flux leakage field. Choosing a suitable lift-off distance will be helpful to get a better magnetic flux leakage field signal.
-
Keywords:
- Pipeline /
- Magnetic flux leakage /
- Finite element method /
- Signal analysis
-
-
[1] 李光海，刘时风，沈攻田．压力容器无损检测——漏磁检测技术［J］．无损检测，2004，126(12)：638-642. [2] 何辅云．石油管道的高速检测与缺陷识别［J］.无损检测，2000，22(5)：206-208. [3] 王亚东．管道漏磁检测技术研究［D］.大庆：大庆石油学院，2004. [4] 徐江，武新军．国外油管在线无损检测技术的研究与应用现状［J］.石油机械，2006，34(5)：81-84. [5] 张勇．漏磁检测若干关键技术的研究［D］.合肥：中国科学技术大学，2007.
计量
- 文章访问数: 6
- HTML全文浏览量: 0
- PDF下载量: 1
下载:
