漏磁检测中提离值影响的三维有限元仿真分析

3-D FEM Simulation of Lift-Off Effects on Magnetic Flux Leakage Testing

随着管道、储罐的推广使用,管道、储罐腐蚀泄漏事故频发.漏磁检测方法是当前最频繁使用的管道无损检测技术.该文应用三维有限元分析方法探讨了漏磁检测方法中提离值对检测结果的影响.首先,根据麦克斯韦方程组推导出缺陷处的三维漏磁场分布;再通过ANSYS软件建立振动条件下的漏磁检测三维有限元仿真建模,分析了不同提离值下缺陷漏磁信号的分布.然后,制造一系列人工缺陷并开展实际漏磁检测实验,以验证三维仿真结果的有效性.最后,通过最小化振动和电磁噪声误差,得到不同尺寸缺陷对应的最佳提离取值.该研究可为检测人员优化探测器结构、提高漏磁检测精度提供有效参考依据.

With the increase of pipelines and steel tanks,corrosion leakage accidents happen frequently.The magnetic flux leakage （MFL）method is currently the most commonly used pipeline inspection technique.In this paper,three-dimension （3-D）finite dement analysis has been used to examine the effect of lift-off on MFL signals.Firstly,according to Maxwell equations,the 3-D MFL field distributions of defects were deduced.Then,the 3-D finite dement simulation model of MFL under the vibration conditions was established in ANSYS and the MFL signals of defects at different lift-off were analyzed.To confirm the 3-D simulation results,a set of artificial defects was made and the MFL experiments were pedormed.Finally,the best lift-off at different sizes of defects was achieved by minimizing the errors caused by vibration and electromagnetic noise.This research can be used to optimize the detector structure to increase MFL detection measurement accuracy.