CONTROLLED HIGH-POWER ACTUATION UTILIZING TERFENOL-D

A high power non-resonant actuator based on the rare earth-iron magnet ostrictive compound Terfenol-D has been constructed and its performanc e evaluated. Two types of spring loading have been applied with differ ent compliancies. Under DC operation the less compliant spring produce d limited displacement with large forces (120 mu m @ 15 kN), whilst th e more compliant load permitted larger displacements and smaller force s (550 mu m @ 3 kN). Calculation of the work done in the latter case i ndicates an internal stress level in the Terfenol-D of approximately 6 .4 MPa. For AC operation sinusoidal peak to peak currents of 28 amps g enerate a nett force of approximately 9 kN, over and above any applied prestress, which decreases by 10% at frequencies up to 400 Hz, Higher frequency components only appear at very high drive levels. (C) 1997 Elsevier Science S.A.