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Proceedings Paper

High-energy absorption in bulk ferromagnetic shape memory alloys (Ni50Mn29Ga21)
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Paper Abstract

Mechanical testing of a bulk, single-crystal sample of Ni50Mn29Ga21 produced large hysteresis loops indicating the potential for the material to be used as a damper. Damping capacity was measured as a function of energy absorbed by the material relative to the mechanical energy input to the system. Tan delta, the tangent of the phase lag between stress and strain, was calculated and shown to increase as a function of maximum strain level. Five strain levels were evaluated (1%, 2%, 3%, 3.5%, and 3.7%) with tan delta values increasing from 0.6 at 1% strain level to 1.1 at 3.7% strain level. The secant modulus of these curves was also evaluated at each strain level to characterize the sample in terms of both damping and stiffness. The maximum secant modulus of 285 MPa occurred at the 1% strain level and decreased to 56 MPa at 3.7% strain. Examining the stress and strain values in the time domain reveals a varying time lag and thus the reported values for tan d are considered an average measure of the material's damping capacity.

Paper Details

Date Published: 21 July 2004
PDF: 9 pages
Proc. SPIE 5387, Smart Structures and Materials 2004: Active Materials: Behavior and Mechanics, (21 July 2004);
Show Author Affiliations
Eric Gans, Univ. of California/Los Angeles (United States)
Chris Henry, Univ. of California/Los Angeles (United States)
Gregory P. Carman, Univ. of California/Los Angeles (United States)

Published in SPIE Proceedings Vol. 5387:
Smart Structures and Materials 2004: Active Materials: Behavior and Mechanics
Dimitris C. Lagoudas, Editor(s)

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