Magnetostrictive particulate actuators: configuration, modeling and characterization

Magnetostrictive particulate actuators (MPAs) that take advantage of easy embedability and remote excitation capability of magnetostrictive particles are proposed as new actuators for smart structure applications. A MPA is configured as a small rectangular polymeric beam with magnetostrictive particles dispersed uniformly. Based on the compatibility condition, a load line equation is developed that relates the free strain with the mechanical stress experienced by the magnetostrictive particles. The load line equation and the magnetoelastic property of the material are used to develop a macroscopic behavior model of a MPA. Characterization experiments are used to find the orientation factor and pre-stress. Experimental work shows that the static performance of MPAs for an applied magnetic field depends on the volume fraction, orientation field, mechanical preload, and the stiffness of the polymeric matrix. In general this actuator can be used where the structure needs to be excited with a large force and small strain over a wide frequency range. For example, embedded in a laminated composite, MPAs can be used as micropositioners, vibration dampers, platform stabilizers, and motors.