Innovative hybrid damper with structural steel and nickel–titanium shape memory alloy bars

Abstract

An innovative structural fuse was developed based on the axial combination of structural steel and nickel–titanium (Nitinol) shape memory alloy (SMA) bars. To investigate the performance of the proposed system, six dampers with different steel and SMA configurations were evaluated experimentally under cyclic loads and the stress–strain curves of the samples were obtained. The results showed that as the amount of structural steel was increased with respect to the SMA, the energy dissipation capacity increased while the re-centring capability decreased and vice versa. An SMA/steel ratio of 1.0–1.5 produced energy dissipation and re-centring in a balanced amount. The proposed device thus has uses the advantages of both structural steel and SMA while limiting their disadvantages, with cyclic energy dissipation and strain recovery being the two contrary characteristics of the proposed dampers. Finite-element (FE) simulations were also conducted and the results were compared with the experimental results in order to verify the FE model. The FE model was able to accurately simulate the proposed hybrid damper.