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Proceedings Paper

Passive damping and velocity sensing using magnetostrictive transduction
Author(s): Ralph C. Fenn; Michael J. Gerver
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Paper Abstract

Magnetostrictive Terfenol-D transducers are an attractive alternative to viscoelastic dampers, and electrodynamic and piezoelectric actuators for damping and self-sensing. These advantages include high stiffness and primary load carrying capability, high power density, low voltages, and low temperature sensitivity. Terfenol-D converts 50 percent of the transducer strain energy into magnetic field energy. Because the Terfenol-D transducer is a primary load carrying member, large amounts of structural energy are converted into magnetic field energy. This magnetic field energy is converted into electric energy by a surrounding coil and dissipated in a resistor to provide damping. The voltage developed in the surrounding coil is proportional to the strain rate of the magnetostrictive material, thus producing a velocity signal. This velocity signal can be used for colocated active damping by controlling coil current based on coil voltage induced by transducer velocity. Experiments using a Terfenol-D actuator capable of 65 microns motion and 1,000 N force showed modal loss factors to 0.22 (relative damping to 0.11) and velocity sensing scale factors to 183 volts/(meter/sec). Room temperature tests of a transducer designed for 77 degree(s)K use showed only 20 percent reductions in damping and velocity signals. Magnetic modeling supports the damping and sensing observations.

Paper Details

Date Published: 6 May 1994
PDF: 12 pages
Proc. SPIE 2190, Smart Structures and Materials 1994: Smart Structures and Intelligent Systems, (6 May 1994); doi: 10.1117/12.175184
Show Author Affiliations
Ralph C. Fenn, SatCon Technology Corp. (United States)
Michael J. Gerver, SatCon Technology Corp. (United States)

Published in SPIE Proceedings Vol. 2190:
Smart Structures and Materials 1994: Smart Structures and Intelligent Systems
Nesbitt W. Hagood, Editor(s)

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