Abstract:

Numerical models have attracted lately a great interest in the academic-scientific field. Many physical phenomena are better understood when these models are used, since they improve the visualization of these phenomena and allow higher flexibility, evaluating many different possibilities by modifying some of the model parameters. Obviously, this flexibility allows the improvement of the model in a less expensive way and in a shorter time than through pure experimentation. It is particularly important that first year students in Engineering are able to visualize in Lab sessions some of the physical phenomena explained in regular sessions. Magnetic materials are introduced in Fundamental Physics, but they keep being used during the whole degree. They are used to understand the behaviour of some electrical devices, such as transformers, or even electronic devices, such as analogue sensors. This paper presents a numerical model that uses the Finite Element Method (FEM). The proposed model shows how magnetic induction lines follow different paths if the macroscopic properties of the material are changed. Isotropic and homogeneous materials without distributed charges or currents are used. When magnetic properties are modified, the second order equations that rule the magnetic field inside a material are still satisfied. The student analyzes the dispersion phenomenon, activating or deactivating different parts of the model. Thus, the comprehension of the field propagation through the structure is facilitated, because the numerical model shows which parts of the device contribute in a more or less significant way to the phenomenon.

Keywords:

Magnetic materials, finite elements, dispersive media, learning and teaching methodologies.