磁弹耦合扭转波位移传感器输出电压理论研究

磁弹耦合位移传感器感应线圈电压是由应力波引起的磁化强度变化决定的,而应力与偏置磁铁处的材料磁导率密切相关,因此磁导率与磁化强度变化率的确定是建立输出电压模型的关键.根据铁磁材料的弹性力学理论和磁机耦合模型,确定了扭转波运动方程;建立材料等效场分布模型,并结合麦克斯韦方程和磁化强度进动方程,确定波导丝磁导率;根据磁机效应的Jiles-Atherton理论,建立了波导丝弹性形变感应磁化强度模型.根据磁导率及磁化强度模型,并借助电磁感应定律构建了感应线圈的输出电压模型.利用实验平台验证了接收线圈匝数和激励脉冲的脉宽、频率对输出电压的影响,为磁弹耦合位移传感器的研究提供了理论依据.

Theoretical Study on Output Voltage of Magnetoelastic Coupling Torsional Wave Displacement Sensor

The coil voltage of Magnetoelastic coupling displacement sensor is determined by change rate of magnetiza-tion by stress waves,which is related to the permeability of the material at the position of bias magnet. Therefore,de-termining permeability and change rate of magnetization is the key to establishing model. Firstly,according to the elas-tic mechanics model and magnetically coupled model of ferromagnetic material,the torsional wave motion equation is determined. Then the magnetic permeability of the wire is obtained by establishing the equivalent field distribution model combined with the Maxwell equation and the magnetization precession equation,and the change rate of magneti-zation is obtained with the Jiles-Atherton theory. Finally,the coil output voltage is obtained according to the law of e-lectromagnetic induction. The effects of coil turns,pulse width and period on the output voltage are proved by experi-mental platform,which provides theoretical basis for the study of magnetoelastic coupling displacement sensor.