Superelastic SMA omega dampers for seismic resilience

Abstract

This paper aims to develop a novel shape memory alloy (SMA) omega damper (denoted as SMA-Ω damper) as a new self-centering component for developing seismic resilient engineering structures. The mechanical behavior and deformation mechanism of the SMA-Ω damper were presented firstly. Experimental studies were subsequently conducted to investigate its hysteretic behavior and failure mode under cyclic loadings. Test results confirmed that the proposed SMA-Ω dampers could achieve reliable self-centering performance with negligible residual deformations under cyclic loadings. Parametric numerical studies were further carried out to understand the strain and stress development in SMA-Ω dampers under cyclic loading and to investigate the influence of design parameters. Parametric analyses revealed that the geometric parameters t, R, r, and d1 governed stiffness, strength, and strain distribution. Larger thickness (t), smaller radii (R, r), and shorter transition lengths (d1) increased stiffness, strength, and energy-dissipation capacity but might induce stress concentration and reduce deformation capacity. Based on the test and numerical results, the design recommendations of SMA-Ω dampers were finally proposed.