Self-centring damper with multi-energy-dissipation mechanisms: Insights and structural seismic demand perspective

An innovative self-centring damper equipped with shape memory alloy elements and wedge-shaped friction plates (i.e. SMA-VFSD) characterised by multiple energy-dissipation mechanisms was developed. First, the notion and rationale of the damper was illustrated. Then, an analytical model enabling quantification of the hysteretic behaviour of the proposed SMA-VFSD was derived. A numerical parametric study using validated modelling techniques was subsequently conducted. The good agreement between the hysteretic responses of numerical models and analytical predictions confirmed the promise of the proposition and the adequacy of the analytical design model. Resorting to the analytical model, sensitivity analyses covering a wider spectrum of design pa-rameters were performed, and the influence of essential parameters on the hysteretic behaviour of the damper was examined. Finally, the constant-ductility-based non-linear spectral analyses of an equivalent single-degree -of-freedom (SDOF) system representing steel frames equipped with SMA-VFSDs were performed to quantify the structural seismic demand and examine the effectiveness of the damper in improving the structural seismic performance. Two conventional self-centring systems characterised by flag-shaped hysteretic features were also studied for comparison. The analysis results showed that the multiple energy-dissipation mechanisms of the SMA-VFSDs are beneficial in reducing the structural inelastic seismic demand, highlighting the potential of the damper towards performance advances in self-centring structures.