Speaker
Description
Magnetostriction is one of the most important properties of ferromagnetic materials, as it couples magnetic and mechanical effects, therefore, mechanical stress is induced under the influence of a magnetic field. In our case, for instance, we put Ferrite rod in the alternating magnetic field that is produced by regular coil and observe its behavior changing frequency of the magnetic field. As the rod undergoes periodical mechanical deformation, longitudinal waves are induced, and consequently, sound is produced by the rod. The main purpose of the investigation is to study these waves.
In the first part of the study, we demonstrate the phenomena, where the experiment shows that different wave modes of the natural order external magnetic field frequency propagate through the rod. Thus, in our theoretical model, which is based on the forced wave equation and the non-linearity of the magnetization of the ferrite rod material, we must consider all boundary conditions properly, in order to qualitatively describe its behavior dependence on the frequency of the alternating magnetic field. Additionally, we will compare the theoretical results to the experimental ones, where we used a microphone to record the sound of the ferrite rod and then performed Fourier analysis. This analysis will allow us to determine the actual relative deformation of the rod as a function of time.
In the last part of the study, we will demonstrate an additional experiment involving a jumping bead on the top end of the rod under several initial conditions. If the amplitude and frequency of the oscillation of the top end are sufficiently high, the bead may lose contact with the surface of the ferrite rod. Moreover, after several collisions, the jumping height may increase. Therefore, this simple experiment can help us estimate the power and efficiency of the ferrite rod.
