Effect of Magnetostriction on Localised Flux Density in Toroidal Amorphous Cores Due To Bending Stress

Abstract

Application of a force causes a localized bending stress, which results in a change in the domain structure and therefore a variation in induced voltages are occurred across search coils uniformly wound on this area. The magnetostriction of amorphous ribbons vary with their compositions. Two types of amorphous ribbon were used to analyse the variation of localised flux density with different flux density and frequency levels. Amorphous toroidal transducers were made from high and near zero magnetostrictive Metglas® as-cast amorphous ribbons, which were Fe-based 2605SA1 and Co-based 2705X respectively. Measurements were carried out to confirm the influence of applying force and frequency on output characteristic of the transducer due to their magnetostriction. A force was applied to the toroidal core in steps of 20 from 0 to 500 g-force. The transducer under the test were sinusoidally magnetised over the frequency range from 1 to 10 kHz and flux density levels of 50, 100 and 150 mT. The variation in the induced voltage of search coils located at 0º and 90º was very significant with applied stress, while it was less pronounced located at 45º with applied stress on the Fe-based toroidal core and the applying force is not effective on 2705X amorphous ribbon. This investigation highlights the influence of localised bending stress on flux density in amorphous ribbon cores due to its magnetostriction.

Key words: Amorphous ribbon core, magnetostriction, flux distribution.

DOI: 10.7176/JSTR/6-07-13