Experimental characterization of superelastic friction dampers with a focus on cyclic response, failure behavior and reparability

This study investigates the experimental response of a hybrid shape memory alloy (SMA) cable-friction damping device with a specific focus on the failure behavior and reparability of the damper when tested at extreme deformations. The superelastic friction damper (SFD) is a hybrid seismic protection device that combines the high tensile strength and re-centering capability of superelastic SMA cables with stable, repeatable energy dissipation of a friction-based damping system. In this paper, the fabrication of a prototype damper and its experimental testing are discussed. The response of the SFD’s friction and self-centering mechanisms were separately evaluated considering design level deformations, cyclic loading, and large deformations up to failure. The performance of the device after the repair of failed components was also investigated. Findings from the study show that the SFD reached failure at a deformation level that exceeded the design displacement by a factor of 2.2. The force capacity of the SFD at the failure stage was 46% higher than the maximum force at the design deformations. After replacing the failed SMA cables, the damper’s mechanical response was identical to the pre-failure response, illustrating the device’s ability to be restored without hindering performance.