Study Of Elastic Waveform Mechanism Of Magnetostrictive Line Position Sensor

Magnetostrictive linear position sensor is a kind of sensor with magnetostrictive effect and inverse magnetostrictive effect. At present, both at home and abroad, the theories and practices on this kind of sensor were focused largely on material preparation, basic materials theory, systems integration etc, but rather the lack of researches on the basis theory of the sensor system.In order to explain the generation mechanism of elastic wave in the sensor system, multi-disciplinary application of knowledge were utilized, such as magnetic, mechanical, electrical, signal, computer simulation, numerical analysis, computer control, and so on. Within the framework of nonlinear coupling theory, the nonlinear problem of multi-field coupling effect was discussed using finite element analysis. The magnetic field distribution data of magnetostrictive line was obtained and the relationship between impulse source and elastic waves were constructed and discussed with the help of numerical analysis and the data from experiments. The easy magnetization direction, fixed end wave and the structure of sensor line were studied, which affect the performance of the sensor system. The study has positive influence on the enhancement of the performance of the sensor.Chapterâ… is an introduction on issues of the background and object of research, content, significance, methods and structure of the framework.In chapterâ…¡, basic theories and concepts of magnetostrictive linear position sensor were described, and the research approaches and relative results associated with the magnetostrictive linear position sensor were introduced, which provided theoretical support for further relevant models discussed. Based on the basic theories and previous works, theory models of elastic wave were constructed, which explained the mechanism of elastic wave. The relationship between magnetic field and characteristics of elastic waveform, the stress field and the distribution of the magnetostriction were discussed.In chapterâ…¢, the important components and key parameters of the magnetostrictive line sensor were studied with special experiments and relative theories. The parameters of the impulse source were delimited based on abundant of experiments and theories. The circumference magnetic field and the permanent magnetic field were detected and analyzed, and further more magnetic field distribution data in the magnetostrictive line were calculated with computer simulation and numerical calculation method. The oscillation phenomena of detecting system were discussed and spectral analyses of collected signals reveal the characteristic of signals in the sensor. Finally, the elastic wave velocity of the material we used was measured with special experiment system.In chapterâ…£, Experimental and assessment platform of the magnetostrictive line position sensor were designed and implemented, using the definite values of impulse source, signal detection and position calculation studied in chapterâ…¢. The distribution data of impulse source were calculated and analyzed based on relative mathematic models established, using the magnetic field distribution data inside the material of magnetostrictive line of the sensor, which resulted from experiments, ANSYS simulation platform and numerical analysis methods. And the relationship between impulse source and the distribution characteristics of stress field, magnetic field and magnetostrictive field were discussed to prove the rationality of the established mathematic model. On the assessment platform, the easy magnetization direction, fixed end wave and the structure of sensor line were studied, which affect the performance of the sensor system.Finally, in chapter V, the research achievements in present phase of the magnetostrictive position line sensor were summarized and the problems existed in the study at present are put forward, as well as the future research orientation.The theory models of elastic waves explained the relationship between input parameters and output signals in the magnetostrictive line sensor. The rationality of the models can be proved with the data resulted from simulated and numerical analyzed. The key parameters of the sensor are discussed by lots of experiments in this paper.