THE EXPERIMENTAL INVESTIGATION OF AMPLITUDE – FREQUENCY CHARACTERISTICS OF CURRENT–CARRYING PLATES IN THE DIRECT MAGNETIC FIELD

MECHANICS

Abstract

The bending waves of forced vibration of electro-conductive and ferromagnetic cantilever plates in direct magnetic field is experimentally considered. It is revealed that for the current–carrying plates, the character of the change in the frequency is essentially different from the analogical change in the same characteristics for the plate with no current. For the cantilever plates, the stability, depending on the influence of the magnetic field (MF), as well as on the quantity of the current and frequency of the forced vibration is investigated. The experiments showed that for the plate placed in a longitudinal field, the increase of the magnetic field brings about an increase in the natural frequency. For the plate placed across the field, the increase of the magnetic field leads to the decrease in the natural frequency, and consequently to the loss of the stability, too. For the plate of comparatively average thickness, the dependency of the vibration frequency is of an experimental character. A point of minimum exists. The experimental character of the dependency “frequency – length of the wave MF” is also shown. It is also necessary to indicate that the character of the change in the frequency, depending on the current for the ferromagnetic plates is essentially different from the analogical dependecy for non- ferromagnetic current–carrying plates.