Abstract The flag-shaped hysteretic behavior of Shape Memory Alloys (SMAs) can be conveniently used for developing efficient isolation systems, providing energy dissipation without implying residual displacements. This work presents a base isolation layout that combines low-friction curved surface sliders (CSSs) with SMA gap dampers (SMAGDs). The proposed SMAGDs are formed by a group of SMA wires placed in parallel with the CSS isolation system and connected to it through a sliding pin and a slotted ring in order to accomplish the “gap damper” feature. Based on this installation configuration, SMAGDs introduce additional stiffening and energy dissipation to the isolation system only when the displacement of the CSS exceeds a certain threshold or gap displacement d gap , while not being engaged for lower displacements. Consequently, the system exhibits a phased behavior, meaning that its reaction force depends on the amplitude of the displacement. This is particularly convenient for limiting seismic displacements while avoiding at the same time undesirable effects such as high structural accelerations and poor re-centering capability exhibited by alternative systems at low-intensity excitations, e.g. systems based on high-friction CSSs or combinations of CSSs with traditional supplemental energy dissipation devices. The paper describes a preliminary design procedure and the evaluation of the seismic performance of the proposed CSS + SMGAGD system. A leading design parameter of the SMAGDs is the overall cross-sectional area of the SMA wires, which is designed here through a direct displacement based procedure, by introducing some reasonable assumptions for the definition of the linear equivalent mechanical properties of CSS, SMAGD and combined CSS + SMAGD system. This performance-oriented design procedure is aimed at achieving a target displacement demand of the combined CSS + SMAGD system under the maximum credible design earthquake. A parametric study comprising a variety of CSS and SMAGD properties reveals that the proposed isolation layout is suitable to limit the maximum displacement under ultimate limit state earthquakes, providing at the same time satisfactory energy dissipation along with high re-centering capability, and outperforms both low-friction CSSs and high-friction CSSs.

中文翻译：

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结合低摩擦滑动摆轴承和基于 SMA 的间隙阻尼器的自适应隔离系统

摘要 形状记忆合金 (SMA) 的旗形滞后行为可方便地用于开发高效的隔离系统，提供能量耗散而不意味着残余位移。这项工作提出了一种将低摩擦曲面滑块 (CSS) 与 SMA 间隙阻尼器 (SMAGD) 相结合的基础隔离布局。提议的 SMAGD 由一组与 CSS 隔离系统平行放置的 SMA 线形成，并通过滑动销和开槽环连接到它，以实现“间隙阻尼器”功能。基于这种安装配置，只有当 CSS 的位移超过某个阈值或间隙位移 d gap 时，SMAGD 才会向隔离系统引入额外的刚度和能量耗散，而在较低位移时不会接合。最后，该系统表现出一个阶段性的行为，这意味着它的反作用力取决于位移的幅度。这对于限制地震位移特别方便，同时避免了诸如高结构加速度和低强度激励下替代系统表现出的不良重心能力等不良影响，例如基于高摩擦 CSS 的系统或 CSS 与 CSS 的组合传统的补充能量耗散装置。本文描述了初步设计程序和拟议的 CSS + SMGAGD 系统的抗震性能评估。SMAGD 的一个主要设计参数是 SMA 线的总横截面积，这里是通过基于直接位移的程序设计的，通过为 CSS、SMAGD 和组合 CSS + SMAGD 系统的线性等效力学性能的定义引入一些合理的假设。这种以性能为导向的设计程序旨在实现组合 CSS + SMAGD 系统在最大可信设计地震下的目标位移需求。包含各种 CSS 和 SMAGD 特性的参数研究表明，所提出的隔离布局适用于限制极限状态地震下的最大位移，同时提供令人满意的能量耗散和高再定心能力，并且优于低-摩擦 CSS 和高摩擦 CSS。这种以性能为导向的设计程序旨在实现组合 CSS + SMAGD 系统在最大可信设计地震下的目标位移需求。包含各种 CSS 和 SMAGD 特性的参数研究表明，所提出的隔离布局适用于限制极限状态地震下的最大位移，同时提供令人满意的能量耗散和高再定心能力，并且优于低-摩擦 CSS 和高摩擦 CSS。这种以性能为导向的设计程序旨在实现组合 CSS + SMAGD 系统在最大可信设计地震下的目标位移需求。包含各种 CSS 和 SMAGD 特性的参数研究表明，所提出的隔离布局适用于限制极限状态地震下的最大位移，同时提供令人满意的能量耗散和高再定心能力，并且优于低-摩擦 CSS 和高摩擦 CSS。