Performance optimization of magnetostrictive guided wave sensor based on waveguide wire

In this paper, an open magnetic circuit magnetostrictive guided wave sensor that allows free regulation of the static working point is proposed for ferromagnetic material waveguide wires applied to non-destructive testing of wire bars, guided wave mechanics study, magnetostrictive linear displacement sensors and other fields. The sensor was made up of an iron-gallium alloy wire, a ring-shaped permanent magnet and a concentric coil, which was used to excited a longitudinal mode guided wave on the iron-gallium alloy wire. The structural parameters of the permanent magnet were optimized, the axial relative distance between the permanent magnet and the coil was studied and the superposition of and matching between the dynamic magnetic field and the static bias magnetic field were adjusted, allowing identifying the optimal magnetization point, so that the magnetic acoustic transduction efficiency was optimized. The sensor was analyzed, by means of finite element simulation, to produce the best system combination, which improved the sensitivity of the measurement. The improvement has been experimentally verified.