Researchers at NASA Glenn Research Center have been investigating high temperature shape memory alloys as potential damping materials for turbomachinery rotor blades. Analysis shows that a thin layer of SMA with a loss factor of 0.04 or more would be effective at reducing the resonant response of a titanium alloy beam. Two NiTiHf shape memory alloy compositions were tested to determine their loss factors at frequencies from 0.1 to 100 Hz, at temperatures from room temperature to 300°C, and at alternating strain levels of 34-35x10^-6. Elevated damping was demonstrated between the M_s and M_f phase transformation temperatures and between the A_s and A_f temperatures. The highest damping occurred at the lowest frequencies, with a loss factor of 0.2-0.26 at 0.1 Hz. However, the peak damping decreased with increasing frequency, and showed significant temperature hysteresis in heating and cooling.

Date Published: 2 April 2008
PDF: 10 pages
Proc. SPIE 6929, Behavior and Mechanics of Multifunctional and Composite Materials 2008, 69291C (2 April 2008); doi: 10.1117/12.776288

Published in SPIE Proceedings Vol. 6929:
Behavior and Mechanics of Multifunctional and Composite Materials 2008
Marcelo J. Dapino; Zoubeida Ounaies, Editor(s)