Dynamic magnetostrain properties of giant magnetostrictive alloy actuators for damping

Giant magnetostrictive alloy (GMA) actuators are tending to replace piezoelectric actuators in many applications owing to their giant magnetostrain and fast response. In an active vibration control system using GMA actuators, the investigation of dynamic magnetostrain can supply the basis for the optimization of actuator designs and control algorithms. Experiments have been carried out under varied operating conditions. The results show that there is a better dynamic output only at suitable prestress and magnetic bias values. For a fixed frequency, the output is basically proportional to the input amplitude but the inclination is slightly different for each input frequency. The natural frequency of the actuator is around 5 Hz and the output displacement decreases with frequency increase after 10 Hz. The dynamic magnetostrain at the natural frequency can be larger than the quasi-static value by up to 40%.