An experimental study on a self-centering damper based on shape-memory alloy wires

Abstract

This experimental study investigates the behavior of a proposed damper based on austenite Nitinol wires. The damper’s design is so that the wires are always in tension under both tensile and compressive forces. Also, the damper can employ steel wires as a hybrid to enhance the performance of the damper. Steel wires can be employed in parallel with the SMA wires and in the same manner. Therefore, SMA and steel wires are stretched simultaneously in the hybrid damper state. This experimental study includes the process of training the wires and the main cyclic tests with different strain rates which leads to the extraction of the hysteresis curves of the proposed damper. A thermal study is also conducted on the employed shape-memory alloy (SMA) wires during the cyclic loadings. The results indicate that the increase of loading frequency causes the SMA wires to heat; thus, the inner area of the hysteresis curve decreases, resulting in diminished damping capacity. Also, the damper stiffness and the residual strain are increased by using the steel wires. The proposed SMA damper is employed for seismic control of a three-story steel frame to evaluate its efficiency. The results reveal that the residual drift ratios of the controlled structure are significantly decreased.

Keywords:

• Passive self-centering damper
• shape-memory alloy wires
• residual strain
• hybrid damper
• heat study

Disclosure statement

No potential conflict of interest was reported by the authors.