基于有限元法的磁层析成像管道应力集中区磁场检测研究

Magnetic Field Detection Research of Stress Concentration Zone of Pipes by Using Magnetic Tomography Based on Finite Element Method

为了解释磁层析成像法测量的磁信号与应力集中区之间的定量关系,提出了基于磁偶极子理论的应力集中区磁场空间传递模型,利用有限元方法计算和分析管道不同位置的应力集中区磁场信号分析形态。设计了实验平台,对含有应力集中区的钢管进行测量,验证了模型分析方法的可行性。结果表明:磁层析成像法能够检测位于管道任意部位的应力集中区磁场,管外空间畸变磁场形态和趋势与应力集中区磁场一致。随着提离值的增加,管外的磁信号强度发生指数性衰减,也说明采用该方法检测位于管道顶部的应力集中区准确率更高。

In order to explain the quantitative relationship between the measured magnetic signal detected by magnetic tomography method and the stress concentration zone,a magnetic field spatial transfer model based on the magnetic dipole theory was proposed,and the finite element method was used to calculate and analyze the magnetic field signal analysis patterns in the stress concentration zone at different positions of the pipeline.An experimental platform was designed to measure the steel pipe with stress concentration zone,and the feasibility of the model analysis method was verified.The results show that the magnetic field in the stress concentration zone located at any part of the pipe can be detected by using magnetic tomography method and the pattern and trend of the spatial distortion magnetic field outside the pipe is consistent with the magnetic field in the stress concentration zone.With the increase of lift-off value,the intensity of magnetic signal outside the pipe decreases exponentially,which also indicates that the accuracy of this method is higher in detecting the stress concentration zone located at the top of the pipe.