An experimental investigation of the pseudoelastic hysteresis damping characteristics of nickel titanium shape memory alloy wires

摘要

An experimental investigation was conducted to determine the pseudoelastic hysteresis damping characteristics of NiTi shape memory alloy (SMA) wires. ^The comprehensive study examines the effects of cycling, oscillation frequency, strain amplitude, temperature, and static strain offset on the pseudoelastic stress-strain hysteresis of SMA wires under axial loading. ^Experimental data are obtained for complete austenite-martensite transformation hysteresis, as well as partial transformation hysteresis. ^The results indicate that as the frequency of excitation increases, the reverse transformation commences at higher stress levels, and the area of the hysteresis loop decreases. ^This results in a rapid initial decrease in energy dissipation, but approaches a stable level by about 10 Hz. ^The energy dissipation at 10 Hz was found to be about 50 percent of that observed at VLFs. ^The energy dissipated at higher temperatures was found to be up to 40 percent lower than that observed at 90 F. ^(Author)