Papers by Keyword: Giant Magnetostrictive Material (GMM)

Abstract: The structure and operation principle of a novel solid MEMS gyroscope with bulk giant magnetostrictive material (GMM) resonator are presented. A finite element method (FEM) for modal analysis of the GMM resonator is employed in which the fundamental magnetoelastic governing equations of the GMM are solved numerically using weak form equations of COMSOL Multiphysics. For a bulk GMM with size of 4×4×4 mm³, it is found that the third order vibration mode with frequency of 182 kHz meets working vibratory mode of the gyro sensor, which is verified by harmonic response analysis. Compared with analogy method which simulates the GMM as piezoceramics, this method is more practically reflect the operation state of GMM resonator of the microgyro due to consideration of Maxwell force in the weak form equations. This paper provides important basis for further full magnetic electromechanical coupling analysis of the microgyroscope.

Abstract: Employing unique advantage of giant magnetostrictive strain of giant magnetostrictive material (GMM) for improving reference vibration amplitude, a novel bulk GMM solid MEMS gyroscope, which has small and simple structure and is capable of detecting 2-axis angular rate with improved sensitivity, is proposed. The device structure and operation principle of the gyroscope are presented. Using finite element method (FEM), modal analyses, for whole solid GMM cube and for bulk GMM cube composed of multilayer GMM plates, are conducted. The results show that the fourth order vibration mode for the former and the first order vibration mode with lower frequency of dozens of KHz for the latter were found to meet the working vibratory mode of the gyro sensor. This work of the paper provides theory foundation for structural optimization design and fabrication of the microgyroscope.

Abstract: In this paper, a kind of giant magnetostrictive material (GMM) model based on inverse magnetostritive effect was developed. Van de Pol nonlinear difference item was introduced to interpret the hysteresis phenomenon of the strain-magnetic field intensity (MFI) curve of GMM. The coupling relationship between strain and frequency was obtained in partial least-square regression method to describe the driftage phenomenon of the strain-MFI curves of GMM in different frequencies. Based on above, the final relationship among strain, MFI and frequency was set up. The result of significance test shows that the effects of all of the items in the final model are remarkable, and that of forecast test shows that the model can describe the characteristics of inverse magnetostritive effect of GMM in different frequencies well. The new GMM model is easy to be analyzed in theory, which is helpful to sensor design.

Abstract: GMHPUT has a wide range of potential application in industrial. However, nonlinearity between exciting current and output displacement spoils GMHPUT’s performance. To explore the nonlinearity behaviors of GMHPUT, a nonlinear dynamic model was established. The bifurcation diagrams, phase portrait, Poincaré mapping diagrams, amplitude spectrum, Lyapunov exponent, etc. which demonstrate dynamical characteristics of the system were obtained by numerical integration. Analysis indicates: Nonlinearity of response could be improved by increasing of damping coefficient. Chaos would appear when stiffness of the system is low. At last experiments were done to verify the model. Calculation results and experimental results show a good agreement.

Abstract: The giant magnetostrictive material (GMM) in dynamic magnetic field has nonlinear and hysteretic characters. Based on the nonlinear constitutive model of the material, the quasi-static hysteresis model with magneto-elastic coupling was built on the Jiles-Atherton model. Considering the eddy current and anomalous losses, the hysteresis model was modified, and the dynamic coupling hysteresis model was established on the basis. Compared with the experimental data, the areas of hysteresis curves increased with frequency, and the maximum magnetostriction strain of the curves increased with prestress. The model agreed well with the experiments within the range of 500Hz.

Abstract: The giant magnetostrictive transducer is a prospective kind of transducer for precession position and actuator utilization. The transducer design need cooperated with the mechanics, electrics and magnetics knowledge. It designs the giant magnetostrictive transducer and employed the finite element method to simulate and analysis the transducer’s prestress mechanism and modal analysis, Meanwhile, It uses the Ansoft software simulated and calculated the electrical and magnetical performance of the designed transducer. It presents the calculating method of the actuator’s mechanical, magnetic and thermal system, and utilizes the finite element method to analysis the actuator’s prestress mechanism, modal mode, permanent and electromagnetic magnetic circuit. The simulation results verified the design is reasonable and effective. The discussion of the model, analysis and simulation method of the transducer can direct the future transducer design and manufacture.

Abstract: To set-up a rate-dependent dynamic hysteresis model, eddy current loss in giant magnetostrictive material is represented by the loss in eddy current impedance. By combining static Jiles-Atherton hysteresis model, the equivalent circuit of giant magnetostrictive material is built, the relationship between eddy current impedance and magnetic field and magnetization is derived and the maximum eddy current impedance of the material is clculated. Effective magnetic permeability is applied to estimate the eddy current impedance as exciting rate or frequency gets high. Simulation and experiment results of exciting frequencies at 5Hz,10Hz,20Hz, are compared, showing experiment results are coincident with simulation ones, in term of magnitude order and tilt direction. It is demonstrated that effective permeability is feasible for eddy current impedance estimation and eddy current impedance-based dynamic Jiles-Atherton hysteresis model is able to reflect practical dynamic hysteresis.

Abstract: SmFe is a kind of giant magnetostrictive material. Though Terfenol-D has a positive magnetostriction constant, SmFe has a negative magnetostriction constant. Furthermore, the permeability of SmFe is bigger than the permeability of a Tb system material. Since the permeability is big, it is expected that the merit is big, when a sensor device is constructed using SmFe. This paper describes an SmFe thin film and a method for introducing stress into the SmFe thin film. Next, the results of measuring the magnetic characteristic using VSM, while the stress is applied, are shown. Finally, it is shown that a highly sensitive force sensor can be constructed using an SmFe thin film, because the differential permeability greatly changes on the SmFe thin film, when tensile stress was applied, from the measured magnetic characteristic.

Abstract: Piezoelectric (PZT) material is widely used to drive micro-positioning platform, but the energy density of PZT is low, which restricts the application of PZT micro-positioning platform. In order to overcome its disadvantages, A kind of new micro-positioning platform actuated by giant magnetostrictive material (GMM) was presented in the paper. Based on integrated optimization method, structure designing, magnetic circuit designing and temperature control designing were carried out. The dynamic performance of GMM micro-positioning platform was simulated, and simulation result shows the designing is feasible. The prototype was manufactured, and the measurement system was set up. The experiments on the platform were carried out, and experiment results show that the platform has good output performance with positioning accuracy of ±0.03μm and load capacity of 50kg, and can meets the requirements of large-power system.

Abstract: The green fixture is the research focus, but the current research is centralized on the fixture driven by the air. It will lead to a noise polution and a small clamping force. Using the green electromagnetic conversion technology, a new clamping system to clamp the workpiece is provided, which is composed of the giant magnetostrictive material as working medium and the displacement amplifier with the area effect. This device can realize the flexible configuration of clamping at multi-place, for multi-workpiece and in multi-direction. Furthermore, this clamping system using the A/D converter and the sensor technology of pressure and displacement to collect the relative data, the collected data can to be putted in the computer and be processed，so it is easy to control the clamp force and clamping displacement intelligently.