Study Of Giant Magnetostrictive Freezing Rain Sensor

Freezing rain is composed of low temperature water droplets. Rain is immediately produced, when the water droplets contact with the object of which the temperature is lower than 0oC. That is a common hazardous weather in early winter or early spring. The damage which is caused by the freezing rain is very large. It has a great influence on agriculture, transportation, communications, public security, plant and animal life safety. Therefore, providing high quality meteorological service is an important problem needed to be solved at present. Giant magnetostrictive materials are new functional materials of high technology, which has excellent characteristics, big expansion coefficient, large output mechanical stress and fast response speed compared with other materials. Based on the harm of freezing rain and the characteristics of giant magnetostrictive material, the magnetic structure of giant magnetostrictive freezing rain sensor was designed. The magnetic field of the freezing rain sensor is analyzed by the finite element software, and the feasibility of the design was verified by the relevant experiments.In this paper, B-H curve and λ-H curve of giant magnetostrictive material were tested and then μ- H curve was calculated. Also the magnetic field of the freezing rain sensor was modeled through the finite element analysis software. The magnetic field distribution under different excitation current density was got, and the parameters design of the excitation coil was completed by calculation. On the basis of the analysis on the natural frequency of the freezing rain sensor, the finite element analysis software was used to simulate the natural frequency of the freezing rain sensor. And the relationship between the natural frequency of the freezing rain sensor and freezing thickness was got. Finally, automatic natural frequency tracking of freezing rain sensor was simply analyzed.