Working in cooperation with the Naval Surface Warfare Center – Carderock Division (NSWCCD) , ETREMA has designed, built, and tested a Galfenol-based actuator capable of generating a force output while operating under tensile strains up to 0.14% (0.0014 in/in) at 300 Hz. Manufacturing challenges addressed included laser welding of Galfenol laminates and fabricating parts to tight tolerances; ± 0.001” on length and ± 0.0004” on flatness and parallelism over a length of approximately 10 inches.

Two prototype actuators were manufactured and tested under quasi-static and dynamic conditions. Dynamic power requirements included 15-16 amps of DC bias and up to 25-26 amps AC (pk-pk). Two cooling fans were used to provide convection cooling of the Galfenol legs and drive coils during dynamic operation.

The actuators were capable of outputting between 1300 – 1600 lbf based on quasi-static testing. Force outputs were registered up to 0.14% applied tensile strain using 300 Hz tones. The magnitude of the dynamic force output was limited by the matched stiffness between the test cell, an MTS 810 load frame, and the prototype actuators. Attachment of the actuator to stiffer loads will produce larger force outputs and the capability to apply larger tensile strains.