钢板缺陷的磁致伸缩SH0模态导波扫查传感器

研制了一种具有优化检测线圈和高激发效率的传感器。通过在矩形截面检测线圈内布置导磁性屏蔽层,减小矩形线圈上、下导线形成的动态磁场的相消程度,在降低线圈高度的同时保持线圈的导波检测能力;采用U型永磁磁路对铁钴合金带材进行恒定磁化,提升传感器的导波激发效率,采用有限元仿真优化了永磁磁路的磁极间距和高度;利用研制的扫查传感器在含缺陷钢板中进行了测试。结果表明:相比剩磁状态,永磁磁路磁化时传感器对回波信号的检测能力明显提升,扫查过程中检测信号波形峰峰值的变异系数小于91.%,具有良好的稳定性。

Scanning magnetostrictive sensor of SH0 guided wave for steel plate defects

A scanning magnetostrictive sensor(MsS)with optimal coil configuration and high excitation efficiency was developed.Magnetic shield was placed inside the rectangular sensing coil to suppress the cancellation effect between the dynamic magnetic fields provided by the upper and lower wire current,respectively.Therefore,the height of the sensing coil can be reduced while retaining the guided wave detection ability of the sensing coil.Ushape permanent magnetizer was employed for realizing stable magnetization of the FeCo strip so that the excitation efficiency of the sensor can be improved.Finite element simulation was used for optimizing the width and height of the yoke.Experimental tests were conducted in a defective steel plate using the proposed scanning MsS.The results show that the guided wave detection ability of the MsS with permanent magnetizer was significantly improved as compared with that was tested under the condition of remanence.The coefficient of variation of the data obtained during the scanning process is less than 9.1%,indicating very good stability of the scanning sensor.