Performance and Repairability of SMA Cable-Friction Devices under Repeated Loading Conditions

This study focuses on the experimental testing of a hybrid SMA cable-friction device at varying displacement amplitudes and loading frequencies. The large-diameter SMA cables serve as the main elements of the device, providing most of force resisting capacity as well as self-centering capability, while the frictional unit of the device augments the energy dissipation capacity. Two prototype self-centering friction devices were fabricated, and their frictional response was studied under varying clamping forces. Next, the behavior of the SMA cables was characterized under varying displacement amplitudes and loading frequencies. The combined damper was then subjected to tests involving different displacement amplitudes, loading frequencies, and a low-cycle fatigue loading protocol to assess its overall performance and durability. The experimental results demonstrate that the proposed SMA-based damper provides a stable response with minimal rate-dependency, reaching a peak force of 116 kN at 40 mm displacement and showing minimal residual displacements upon unloading. Despite some strand rupture in one SMA cable after over 100 cycles, the damper maintained its load-carrying capacity, indicating redundancy and ease of repair by replacing individual SMA cables.