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.

摘要

本实验研究调查了所提出的基于奥氏体镍钛诺线的阻尼器的行为。阻尼器的设计使钢丝在拉力和压力下始终处于张力状态。此外，阻尼器可以使用钢丝作为混合材料以增强阻尼器的性能。钢线可以与 SMA 线并联并以相同的方式使用。因此，SMA 和钢丝在混合阻尼状态下同时拉伸。该实验研究包括训练线材的过程和不同应变率的主要循环测试，从而提取所提出的阻尼器的滞后曲线。在循环加载期间，还对所使用的形状记忆合金 (SMA) 线材进行了热研究。结果表明，加载频率的增加导致SMA线材发热；因此，滞后曲线的内部区域减小，导致阻尼能力降低。此外，通过使用钢丝增加了阻尼刚度和残余应变。所提出的 SMA 阻尼器用于三层钢框架的抗震控制，以评估其效率。结果表明，受控结构的残余漂移率显着降低。