The Effect of the External Magnetic Field on the Initial Impulse Attribute for Magnetostrictive Sensors

Magnetostrictive sensors (MsS) using the magnetostriction effect have many advantages for nondestructive inspections, such as without any contact, movable and easily installed. While the shortcoming of MsSs, for example low SNR, the output affected by the nonlinear magneto-mechanical coupling performance under magnetic field can limit the use of it. In order to solve this problem, the mechanical dynamics model to excite guided-wave was established which was based on the nonlinear coupled magnetostrictive theory of ferromagnetic material and the generator model of magnetostrictive guided-wave. Using a finite element method and numerical simulation, the effects of the bias magnetic field, exciting frequency and exciting current on the particle amplitude were analyzed. The results indicate that the low frequency, heavy current and suitable bias magnetic field can improve the conversion efficiency of magnetomechanical coupling performance under the condition of considering dispersion. The suitable bias magnetic field is determined by the maximum tangent slope of the amplitude curve.