基于黏滞阻尼-SMA耦合机制的钢结构自复位机理研究

The good energy dissipation ability exhibited by steel structures is normally at the cost of permanent deformation and large residual drifts, leading to significantly increased repair cost after strong earthquakes. As an effective means of increasing the post-earthquake resilience of steel structures, the current self-centering technology has a number of unresolved issues related to self-centering force applying strategy, energy dissipation ability, peak dynamic response control, and deformation compatibility. To potentially address these issues, a new self-centering design concept based on viscous damping-shape memory alloy (VD-SMA) hybrid technology will be proposed in this study. Employing quasi-static and dynamic tests, multi-scale numerical modelling, and theoretical analysis (including IDA and pushover), the current study will be conducted at element, member, and structure levels. Firstly, innovative SMA elements and members with a completely new working mechanism will be proposed, and the working principle and mechanical properties will be examined. Analytical models will also be established for the SMA elements and members. Subsequently, appropriate structural forms will be established. The dynamic response, energy dissipation mechanism, self-centering driving mechanism, and deformation compatibility of the structures will be fully revealed, and a RID prediction model will be established. Finally, optimal combinations among SMA members, viscous dampers, and the main structural frame will be recommended, and a complete set of design approach will be proposed. If successfully conducted, this study will form important basis on the theory and application of self-centering steel structures, and will provide technical incentives for the application of smart materials in structural design. Therefore, this study is of significant technical importance and will be of great societal benefit.

钢结构强震后会因永久损伤和残余变形而失去修缮价值。作为提高结构震后恢复力的重要手段，当前的自复位技术在施力策略、耗能能力、峰值响应控制以及变形协调等方面存在诸多难题亟待解决。本项目针对现有不足，提出基于黏滞阻尼-形状记忆合金（SMA）耦合机制的自复位钢结构设计理念，利用静、动力试验、多尺度数值模拟、IDA和pushover等分析方法，从元件、构件到体系分层次开展研究：提出基于全新受力特征的高性能SMA元件与抗震构件，揭示其工作机理与力学性态，建立恢复力模型；提出合理的结构体系形式，深入阐明其在全程地震作用下的动力响应规律、耦合耗能机制、自复位驱动机制和变形协调特征，建立结构的残余变形预测模型；最终确定SMA构件、黏滞阻尼和主框架三者之间的最优匹配方案，实现完善的体系设计方法。研究成果不仅为自复位钢结构的推广应用提供科学依据和技术支撑，同时将促进功能材料在结构领域的应用，具有长远的社会效益。

虽然自复位结构是实现结构震后功能恢复的重要方式之一，但大震下仍会产生显著的层间位移、较大的楼面加速度以及连带的结构损伤。降低强震下结构的峰值动力响应、排除关键隐患、保证可靠的自复位能力，是目前该领域研究亟需解决的关键问题。本项目提出了基于黏滞阻尼-SMA耦合机制的自复位钢结构设计理念，采用足尺试验、数值模拟与理论分析相结合的技术手段，基于元件、构件、体系三个层次进行深入研究，主要研究内容和成果如下：1）研究了大尺寸SMA环簧的制作工艺、热力学特性与工作机理，给出了高效的几何与接触设计方案，探明了往复荷载作用下的滞回特性与骨架曲线，给出了准确的力学模型；2）开发了两大类自复位功能构件：SMA环簧自复位节点与SMA环簧防屈曲自复位支撑，明确了其制造工艺、构造措施与工作机理，揭示了两类构件在往复荷载下的滞回特性、形变特点与失效模式，开展了足尺试验验证，建立了准确的构件力学模型；3）开展了基于黏滞阻尼-自复位耦合机制的结构体系抗震机理研究，首先以单自由度体系为切入点，阐明了自振周期、强度、强化刚度、阻尼比、相对耗能比等关键因素对性能指标的影响规律，建立了抗震指标与不同参数之间的关联函数，确定了基于不同性能目标的参数推荐范围。进一步开展了基于黏滞阻尼-自复位耦合机制的钢框架结构抗震性能研究，深入揭示了强震下结构的动力性态、损伤演化特征、耦合耗能机制与自复位驱动机制；4）开展了结构易损性分析，全面统计了性能超越概率分布规律；给出了具有统计意义的结构最大非弹性变形比与残余变形的预测模型，明确了自复位构件、黏滞阻尼器与主结构梁柱构件的参数配合原则，建立了关键构件与整体体系的设计方法，给出了明晰的设计理论。本项目成功推动了自复位钢结构抗震设计理论的创新与突破，为实现钢结构体系（尤其是具有重要使用功能与高性能水准的钢结构体系）震后功能的快速恢复提供了科学依据和技术支撑。