为解决传统阻尼器屈服后刚度和强度不足的问题,基于分阶段抗震设计理念,研发一种基于位移放大型变刚度自复位阻尼器(self-centering dampers based on variable stiffness and displacement amplification,SDVD),能够兼顾结构在不同变形阶段的刚度和承载力需求.该阻尼器主要由子模块初始刚度模块(initial stiffness module,ISM)和变刚度模块(variable stiffness module,VSM)组成,基于阻尼器的构造,分析其子模块及整个阻尼器的工作机理;以ISM和VSM的长度和宽度为参数,设计并制作模块ISM和VSM及SDVD整体的模型试件,通过拟静力试验研究子模块及整个阻尼器的滞回性能;通过有限元模型(finite element model,FEM)研究阻尼器滞回性能的参数影响规律.研究结果表明:该阻尼器表现出拉压对称的旗帜形滞回特性,同时具有位移放大效应和变刚度特性;通过对比分析,由有限元分析得到的阻尼器滞回曲线与拟静力试验结果吻合较好;SDVD的初始刚度和强度主要由ISM提供,并且随着ISM丝束长度的减小而增加;SDVD的屈服后刚度和承载力主要由VSM提供,且随着VSM挡杆宽度的减小而增加.
Study on hysteretic performance of self-centering dampers based on variable stiffness and displacement amplification
To solve the problem of insufficient post-yield stiffness and strength of SMA dampers,a self-centering damper based on the concept of phased seismic design and variable stiffness and displacement amplification(SDVD)has been developed,which can satisfy the stiffness and strength requirements of structures at different deformation stages.The damper mainly consists of sub-modules initial stiffness module(ISM)and variable stiffness module(VSM).Based on the construction of the damper,the working mechanism of the sub-modules and the whole damper was analyzed.The length and width of ISM and VSM were used as the parameters to design and fabricate the model specimens of the modules ISM,VSM,and SDVD as a whole,and the hysteresis performance of the submodules and the whole damper was investigated by pseudo-static test.The parameter influence law of the hysteresis performance of the damper was studied by finite element model(FEM).The results show that the damper exhibits flag-shaped hysteresis characteristics with tension-compression symmetry,as well as displacement amplification effect and variable stiffness characteristics.The hysteresis curves obtained from the FEM analysis of the damper match well with the results from the pseudo-static test through comparative analysis.The initial stiffness and strength of the SDVD are mainly provided by the ISM and increase with decreasing ISM fillet length.The post yielding stiffness and strength of the SDVD are mainly provided by the VSM and increase with decreasing VSM stopper width.
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