基于隧道磁阻阵列的钢索断丝检测传感器研制

摘要

为将新型高灵敏度磁敏元件——隧道磁阻(TMR)器件应用于钢索断丝漏磁检测,采用带磁屏蔽层的类赫姆霍兹线圈作为励磁结构,设计了基于柔性印刷电路的隧道磁阻圆环阵列,可实现对直径为14 mm钢索表面断丝处漏磁场的检测.利用加工有全环向沉槽的钢杆试件,测试7个TMR阵元的一致性,结果表明,宽、深均为0.5 mm的沉槽缺陷检测信号幅值均值约33 mV,信噪比可达14.5 dB,而7个阵元输出电压的极限误差为±1.85 mV.将研制的隧道磁阻阵列传感器应用于钢索表面6处位置不同的断丝缺陷检测,依据检测信号或扫查成像结果,可以清晰分辨出单根0.5 mm断丝缺陷,并确定各断丝在轴向和周向的位置.%In order to apply the advanced tunnel magneto-resistive(TMR)devices for broken-wire flaws detection in steel wire rope based on magnetic flux leakage(MFL)method,a circumferential TMR sensor array was designed in this work.The Helm-holtz-like coil together with a magnetic shield was used as magnetizer for magnetizing the wire rope with a diameter of 14 mm,and the circumferential TMR sensor array was attached onto a flexible printed strip.The consistency of all the seven TMR elements was tested in a defective steel rod.When the sensor array moving through a full circumferential groove defect with a depth and a width of 0.5 mm,the induced MFL signal has an average amplitude of 33 mV with a signal to noise ratio of 14.5 dB and the limit error of the signal amplitudes is about ±1.85 mV.Then the circumferential TMR sensor array is applied for detecting single wire(with a diameter of 0.5 mm)broken flaws in the steel rope.The MFL signal induced by all the six flaws can be identified from the detec-tion signal.In the scan imaging results,the exact axial and circumferential location of each flaw can be determined.