基于GMR效应的金属磁记忆检测方法与应用

Metal magnetic memory testing method and application based on GMR effect

针对铁磁性构件疲劳暗伤部位产生的磁记忆信号特征,采用基于GMR效应的金属磁记忆检测方法,开发出一套基于GMR效应传感器的磁记忆检测系统。以TI公司TMS320LF2407A芯片为处理器核心;信号放大采用差分放大器,提高系统抗干扰能力;采用16位A/D转换芯片提高数据采集精度;采用自适应滤波运算去除信号中的混杂噪音。最后对5个不同应变阶段510 L车桥板材的拉伸试样磁记忆检测信号进行分析,结果表明:基于GMR效应的磁传感器能够灵敏、精确地检测出铁磁性试样的磁记忆信号Hp(y),灵敏度达到6.9 mV/(A·m-1);铁磁性材料试样在进行拉伸试验时,随着拉伸试样载荷的增加,磁记忆信号在过零点处的梯度值也随之增大。

A GMR sensor-based system is developed to detect the magnetic memory signals of damages in ferromagnetic components based on the GMR effect of metal magnetic memory testing. The TMS320LF2407A chips from TI are used as the processor. The differential amplifiers are used as its signal amplifier to improve the anti-interference ability of the system and 16-bit A/D conversion chip is used to improve the accuracy of collected data. The adaptive filtering is used for removing the mixed noises from signals. Five strain samples of 510 L are inspected by the developed system. The results show that magnetic memory signal Hv （y） from the magnetic iron samples can be detected accurately and sensitively based on GMR sensors. The sensitivity of the system is 6.9 mV/（ A · m^ -1 ）. It also shows the gradient of the signals at the zero-crossing point increase when the tensile loads increase in the tensile testing.