Project Title:

Passive and Active Damping Enhancement Using Magnetostrictive Transduction

92-1-09.06-0540                                                   NAS08-39828
Passive and Active Damping Enhancement Using
     Magnetostrictive Transduction
Satcon Technology Corporation
12 Emily Street
Cambridge, MA  02139-4507
Ralph C. Fenn                                        (617-661-0540)

Abstract:

     The controller-to-mass ratio of space structures can be
reduced by devices which combine sensing and actuation functions.
Magnetostrictive materials are well-suited for self-sensing but
have typically been used only for actuation. "Reverse"
transduction from the mechanical into the electrical domain
presents the opportunity to remove large amounts of strain energy
from the magnetostrictive material and the adjacent structure.
This project describes how the effective material loss factor of a
magnetostrictive material can be very high when used with a
passive dissipation network. This method of damping is superior to
competing piezoelectric, viscoelastic, and proof-mass dampers
because of its low mass, low volume, durability, mechanical
simplicity, low voltages, remote dissipation capability, and
temperature insensitivity. This project will also address the use
of magnetostrictive transducers to sense strain rate for active
damping enhancement. Both techniques will provide high damping,
bandwidth, and resolution in a low mass device suitable for use in
space structures. This work includes modeling and optimizing a
passive magnetostrictive damper. A magnetostrictive strut will
also be modeled as a velocity sensor, optimized for active
control, and tested for its validity. A Phase II application will
be determined, and a baseline configuration and network will be
designed. The expected result will be a low mass, self-sensing
magnetostrictive damper design with high loss factors, high
bandwidth, and high resolution.

Potential Commercial Application:

Potential Commercial Applications:  The magnetostrictive damper
will be dramatically lighter, smaller, mechanically simpler, and
less temperature sensitive than existing designs. Lightly damped
structures such as robotic arms will benefit from the design's
high damping, low mass, small size, and zero backlash. Machinery
and vehicle vibrations and noise will be damped by
magnetostrictive struts used as mounts and structural members.

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