Manufacturing and performance of a novel self‐centring damper with shape memory alloy ring springs for seismic resilience

Abstract

This paper discusses the manufacturing process and mechanical performance of a novel self-centring damper equipped with a group of kernel elements, namely, shape memory alloy (SMA) ring springs. The study commences with an experimental investigation on individual SMA ring spring specimens, enabling a fundamental understanding of their working principle and mechanical performance. Some technical issues related to manufacturing process, low-temperature heat treatment (annealing), quenching, and cyclic training are also discussed. Subsequently, the fabrication steps and working mechanism of the dampers incorporating the SMA ring springs are elaborated, and a further experimental study on a large-scale prototype damper specimen is carried out. The test results show that the damper specimen exhibits satisfactory mechanical behaviour with a stable flag-shaped load–displacement hysteretic response. A high initial stiffness and an adequate level of “yield” resistance are exhibited due to a relatively high preload applied to the SMA ring spring group. Excellent self-centring capability with no residual displacement is observed, and satisfactory energy dissipation with an equivalent viscous damping ratio of up to 18.5% is shown. No failure to any component of the damper is observed by the end of the test. The proposed damper is expected to resist strong earthquakes and offer self-centring driving action effectively for engineering structures without the need for repair.