Superelastic SMA U-shaped dampers with self-centering functions

• Published in: Smart materials and structures Vol. 27; no. 5; pp. 55003 - 55016
• Main Authors: Wang, Bin, Zhu, Songye
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.05.2018
• Subjects: flag-shaped hysteresis loop; seismic resilience; self-centering; shape memory alloy; strain rate; superelastic
• ISSN: 0964-1726; 1361-665X
• DOI: 10.1088/1361-665X/aab52d

As high-performance metallic materials, shape memory alloys (SMAs) have been investigated increasingly by the earthquake engineering community in recent years, because of their remarkable self-centering (SC) and energy-dissipating capabilities. This paper systematically presents an experimental study on a novel superelastic SMA U-shaped damper (SMA-UD) with SC function under cyclic loading. The mechanical properties, including strength, SC ability, and energy-dissipating capability with varying loading amplitudes and strain rates are evaluated. Test results show that excellent and stable flag-shaped hysteresis loops are exhibited in multiple loading cycles. Strain rate has a negligible effect on the cyclic behavior of the SMA-UD within the dynamic frequency range of typical interest in earthquake engineering. Furthermore, a numerical investigation is performed to understand the mechanical behavior of the SMA-UD. The numerical model is calibrated against the experimental results with reasonable accuracy. Then, the stress-strain states with different phase transformations are also discussed.