Experimental study of new axial recentering dampers equipped with shape memory alloy plates

Abstract

The most important issues that researchers are faced with are extensive damages and permanent deformations in the structures after earthquakes. This study proposes new hybrid smart dampers combined with shape memory alloy (SMA) plates, friction devices, and polyurethane springs (e.g., ASFP damper) with an aim to decrease structural damage as well as to mitigate residual deformation in the concentrically braced frames (CBFs). These dampers are simply fabricated, and the other parts are low cost except for the nitinol SMA plates. In addition, they can be employed for not only new construction but also rehabilitation of existing structures. In order to investigate the behavior of each key component (e.g., SMA plates, friction devices, and polyurethane springs), eight different cases are experimentally investigated under quasi-static cyclic loading, and the effects of all components are evaluated in this study. In four cases, the SMA plates are replaced by the steel plates to better understand the effect of SMA plates on recentering capability. The details of experimental tests are described with more details. The final results demonstrate that the SMA dampers can restore more than half of residual displacement. In addition, these SMA dampers exhibit stable energy dissipation and adequately operates under both compressive and tensile loading.