Actuators, transducers and motors based on giant magnetostrictive materials

Rare earth-iron magnetostrictive alloys, especially Terfenol-D, feature ''giant'' magnetostrains: static strains of 1000-2000 ppm and dynamic strains of 3500 ppm are reported. These strains permit building various actuating devices (actuators, transducers, motors) both at macro and micro scale. The object of the paper is to recall adapted design methods, especially finite element methods such as ATILA, and to review these different kinds of devices studied at Cedrat Recherche, providing both up-dated experimental and numerical results. The presented devices will include several large displacement longitudinal and shear actuators biased using permanent magnets and used either as characterisation devices or as electromechanical actuators (for active damping, for sonar transducers...), a 1 kHz 4 kW Tonpilz-type sonar transducer called the Tripode, a 2 N m torque rotating Multi-Mode Motor, a torsion based drift free micro actuator and a wireless linear micromotor. (C) 1997 Elsevier Science S.A.