Giant Magnetostrictive Actuators for Ultracompact Electric Vehicles: Analysis of Output Characteristics

Ultracompact electric vehicles have compact, lightweight bodies with low outer-plate rigidity. This results in the transmission of road noise from the tires and wind noise (caused by the projection shape of the vehicle) into the cabin. Interior acoustic control systems require devices that can produce sound waves. Next-generation mobility uses giant magnetostrictive actuators (GMAs) for sound production. This is a foundational study for designing GMAs that can be used in such interior acoustic control systems. Magnetostriction forces are generated when a magnetic field deforms giant magnetostrictive materials. The output characteristics were analyzed by electromagnetic-field analysis. Further, the GMA magnetostriction force was analyzed using the finite element method (FEM)—across varying frequency ranges of piezoelectrically controlled amplifiers. The FEM results indicated that the GMA output performance was sufficient to generate sound waves for active noise control in the low-frequency range, 100–500 Hz (road noise). Further optimization is required to expand the frequency range—to accommodate music playback, etc.—including modification of the actuator size, weight, shape, and components and using materials with higher magnetic permeability.