Novel closed magnetic circuit with permanent magnet biased for giant magnetostrictive actuator

The magnetic circuit of giant magnetostrictive actuator(GMA) was analysed and optimized with finite element software ANSYS. According to the design goals of high homogeneity of magnetic field and low magnetic flux leakage, a novel magnetic circuit biased by the combination of built-in permanent magnets was proposed in the base of compensation principle of dual-permanent magnets with contrary polarity. Magnetic field along the direction of the length of giant magnetostrictive rod was homogeneous, while well-closed magnetic circuits were informed in both biased magnetic field and driving magnetic field. According to the results from ANSYS analysis, the unevenness of the bias magnetic field and driving magnetic field is 3.51% and 8.73% respectively, which are less than 10%. The total magnetic leakage in the specified location(7 cm from the GMA) is 30.4 A/m, meeting the standard of practical application(<80 A/m).