Model And Experimental Study Of Giant Magnetostrictive Vibration Sensor

The giant magnetostrictive material Terfenol-D has a reverse magnetostrictive effect, and a magnetostrictive vibration sensor can be designed based on this effect. The vibration sensing technology, based on the reverse magnetostrictive effect, possibly develop a new vibration sensor to be widely used in vibration testing and vibration control, which would speed up the development in vibration testing and controlling. To provide the groundwork of the optimizing design and application of the magnetostrictive vibration sensor, the model and experiment of the sensor are selected as the subject of dissertation for Ph.D. The main research work is following:1. The relationship between strain and compressive stress under different bias magnetic fields of the core element Terfenol-D in magnetostricitve vibration sensor is researched. The results show that the relationship between them is complex and nonlinear when the longitudinal bias magnetic field acts on Terfenol-D, the Young's modulus dependence of the magnetic fields andΔE effect are acquired from the relationship between strain and stress. The curve of strain and stress under variable bias magnetic fields is explained through magnetic domain theory and magnetic permeability. The experiments of the stress and magnetic induction under different bias magnetic fields are carried out, the results show that the magnetic induction is maximal when the bias magnetic field is 5kA/m.2. A model of giant magnetostrictive transducer under AC driving magnetic fields and dynamic stress is presented, based on the Jiles-Atherton model, the magnetic principle and the transducer's structural dynamics principle. The output displacement, output force and the sensing voltage of the sensing coils are computed when the transducer is under both AC driving magnetic fields and dynamic stress.3. When the magnetic field is AC driving field and the stress is constant, the transducer works as an actuator, then the above mentioned model can be used to compute the relationship between the output displacement and the input current. The experiments of the transducer are processed, and it is found that the computing results and experimental ones are coincident on the whole. When the stress is dynamic and the magnetic field is constant, the transducer works as a sensor, and the above mentioned model can be used to compute the sensing voltage of the sensor.4. An experimental study on the sensing voltage of the sensor is carried out to determine the relationship between the peak to peak value of the voltage and the driving force as well as the bias magnetic field. Experimental data are in a good agreement with computing results. Some experimental data are processed beforehand with averaging method and five points-thrice smoothing technique, then they are filtered with Fourier transformation, and the white noise is eliminated.5. The transfer function of the magnetostrictive vibration sensor is founded based on the electromechanical transform theory of Terfenol-D and mechanical accepting theory of inertial sensor, the model can describe the change of sensor's output voltage and input vibration. The time domain analysis, frequency domain analysis, and sensitivity analysis of the sensor are finished in the paper. The simulation of low frequency compensation is processed based on zero -pole configuration theory, and the parameter is useful to low frequency compensation of the sensor.