Study On Theroy And Applicaton Of Vector Magnetic Hysteresis Mathematical Model

Vector magnetic hysteresis mathematical model is a mathematic tool which can be used to describe the magnetization process of magnetic material under applied field. The fundamental difference between the vector hysteresis model and a scalar hysteresis model is that the former takes the angle between magnetization intensity and magnetic flux density into account while the latter does not. Study of the vector magnetic hysteresis model for magnetic material is a hot topic in the field of material modeling. Grounded on the original Jiles-Atherton scalar magnetic hysteresis model, researches of the vector magnetic hysteresis model for two kinds of materials, NdFeB permanent magnetic materials and giant magnetostrictive material (Terfenol-D), are developed in this thesis.At first, in the aspect of magnetic property modeling, based on the original Jiles-Atherton scalar model and Preisach vector model, a vector Jiles-Atherton magnetic hysteresis model is proposed, and a computer program of magnetic field finite element analysis considering vector magnetic hysteresis is developed. The magnetic field of a single permanent magnet magic ring is analyzed using the program and the effectiveness of the proposed vector Jiles-Atherton magnetic hysteresis model is verified. Moreover, based on the inverse Jiles-Atherton magnetic hysteresis model, a dynamic strain magnetic hysteresis model and a magnetic hysteresis loss calculation model are proposed for a magnetostrictive ultrasonic transducer. A time-step finite element analysis computer program combined the proposed models for magnetic field analysis of the transducer is developed.Secondly, the abnormal magnetization problems of local saturation, local demagnetization, and rotating magnetization of the NdFeB permanent magnetic materials used in the magic ring above mentioned, which occur during the assembling and operating process of the magic ring, may cause failure of a design of the magic ring. To solve the problem, the three abnormal magnetization phenomena are simulated using the proposed magnetic hysteresis model with the related program, and the dynamic magnetic field of an adjustable high field permanent magnetic magic ring is analyzed. A design of the magic ring with the average magnetic flux density between 0.25 and 3.39T is proposed. Besides, in the giant magnetostrictive ultrasonic transducer, the magnetic hysteresis loss, as main heat source, may result in the temperature of giant magnetostrictive materials reaching or exceeding the Curie temperature, which will make the material invalid. To solve this problem the proposed dynamic strain magnetic hysteresis model and magnetic hysteresis loss calculation model are used. Furthermore, the problem that strain effect cannot be taken into account in the calculation of magnetic hysteresis loss is resolved. The magnetic hysteresis losses calculated are introduced as thermal sources into ANSYS software and a process of thermal finite element analysis for Terfenol-D ultrasonic transducer is completed. The temperature increase of the material Terfenol-D is obtained.Finally, the effectiveness of the vector Jiles-Atherton magnetic hysteresis model for NdFeB permanent magnetic materials and the magnetic hysteresis losses model for Terfenol-D is verified through the comparison of the calculated and measured results.