Contactless detection of bending sensitive magnetostrictive bilayers utilizing higher harmonics

Abstract

The study concerns a novel contactless sensor system based on a multifunctional magnetostrictive bilayer material. The permeability of the bilayer ribbons is sensitive either to bending or temperature. The higher order harmonics which are generated by the bilayer in response to a magnetic interrogation field are detected. Their amplitudes depend on the bilayer's permeability, hence on the quantity to be measured. The detection of the third harmonics proved to be most efficient. The sensor system enabled contactless measurements with a distance up to 1 m using a bilayer of only 80 mm in length and 0.1 mm in thickness.