This study proposes a new self-centering, shape memory alloy bar-based device to address the tension-compression asymmetry and limited energy dissipation capacity of similar SMA bar-based devices. The proposed device, named the Confined Superelastic Friction Damper (CSFD), employs buckling-restrained SMA bars to maintain symmetry in force-displacement responses and enhance effectiveness in both tension and compression. The device also integrates a frictional damping mechanism, contributing to increased energy dissipation capacity. First, an optimal annealing condition is investigated for as-received SMA bars to achieve a satisfactory superelastic response. Then, the working and design principles of the CSFD are outlined. The experimental characterization of CSFD devices in various configurations is conducted under an increasing amplitude loading protocol. The devices are tested with different levels of frictional damping to assess the effects of the added frictional forces on device characteristics. Analysis of test results considers parameters such as hysteresis curves, maximum force, equivalent viscous damping, and self-centering efficiency to provide a comprehensive performance evaluation of each device. Findings reveal that while a single buckling-restrained SMA bar device exhibits up to 90 % higher forces in compression than in tension, a CSFD device with two such bars nearly eliminates this asymmetry. Compared to tension-only SMA devices, capable of symmetric response, the proposed CSFD device demonstrates a 2.6 times higher force-resisting capacity. For all devices, the addition of some frictional damping improves the energy dissipation and equivalent viscous damping capacity, while leading to some reduction in self-centering efficiency.

中文翻译：

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有限形状记忆合金棒自定心摩擦阻尼器的开发和表征


本研究提出了一种新型自定心形状记忆合金棒装置，以解决类似 SMA 棒装置的拉压不对称性和能量耗散能力有限的问题。所提出的装置名为受限超弹性摩擦阻尼器 (CSFD)，采用屈曲约束 SMA 杆来保持力-位移响应的对称性，并增强拉伸和压缩的有效性。该装置还集成了摩擦阻尼机制，有助于提高能量耗散能力。首先，研究了 SMA 棒材的最佳退火条件，以实现令人满意的超弹性响应。然后，概述了CSFD的工作和设计原理。各种配置的 CSFD 装置的实验表征是在增幅加载协议下进行的。使用不同级别的摩擦阻尼对设备进行测试，以评估增加的摩擦力对设备特性的影响。测试结果分析考虑了迟滞曲线、最大力、等效粘性阻尼和自定心效率等参数，以对每个设备进行全面的性能评估。研究结果表明，虽然单个屈曲约束 SMA 杆装置在压缩时表现出的力比拉伸时高出 90%，但具有两个此类杆的 CSFD 装置几乎消除了这种不对称性。与能够对称响应的仅张力 SMA 装置相比，所提出的 CSFD 装置的抗力能力高出 2.6 倍。对于所有设备，增加一些摩擦阻尼可以提高能量耗散和等效粘性阻尼能力，同时导致自定心效率有所降低。