Enhanced response from field-annealed magnetoelastic strain sensor

Abstract

Magnetoelastic materials permit the development of remote-query strain sensors for use in situations of difficult access. In this work, we examined materials for a remote-query strain sensor based on the ΔE effect. An applied stress modifies the magnetic field produced by a transducer glued to the sample and thereby changes the resonant frequency of a vibrating amorphous ribbon. We considered several amorphous alloys for both the vibrating ribbon and the transducer. To eliminate the casting stress and improve the anisotropy, ribbons were annealed in a transverse magnetic field. This resulted in a dramatic improvement in the sensor performance when sensors were biased above the anisotropy field. For example, a Metglas 2826MB3 ribbon with resonant frequency of 62 kHz showed frequency shifts of up to 5 kHz for a deformation of 0.03%. These results are in good agreement with models for the ΔE effect.