根据磁致伸缩效应和光纤腔衰荡技术设计了高灵敏度的磁场传感器。基于Jiles-Atherton模型、二次畴转模型和光纤衰荡技术波长解调原理,建立了磁场传感器的数学模型,模型反映了磁场一应变一光纤腔衰荡时间之间的耦合机制。对不同预应力作用下Terfenol-D棒的磁致伸缩输出应变、衰荡时间、系统灵敏度与磁场之间的变化规律进行了理论分析和仿真研究,结果表明,该传感器具有很高的灵敏度,可通过改变预应力实现不同量程范围内的磁场测量,研究可为发展新型的高灵敏度磁场传感器提供了理论指导。
A high-sensitivity magnetic field sensor is designed based on magnetostriction effect and fiber-loop cavity ring- down technique. A mathematic model of the magnetic field sensor is presented according to the Jiles-Atherton model, quadratic magetic domain rotation model and the demodulation principle of fiber-loop cavity ring-dowrt technique. The model quantifies the coupling mechanisms among the magnetic field, strain and the ring-down time of the fiber loop. The strain variation of a Terfenol-D rod, the ring-down time of the fiber loop and the sensitivity of the sensor with the magnetic field are analyzed and simulated under different prestresses. Results show that the sensitivity of the sensor is very high and the measurement range of the magnetic field sensor can be changed by changing the prestress. The study result can pro- vide a theoretical foundation for the development of new high-sensitivity magnetic field sensors.