新型自复位SMA阻尼器对框架结构减震控制的研究

Study on seismic response control of frame structure using innovative re-centring SMA damper

利用形状记忆合金(SMA)的超弹性提出一种新型自复位SMA阻尼器,该阻尼器由预应变SMA丝束和非预应变SMA丝束连接4块钢板组成,具有良好的耗能及复位功能,且构造简单、传力明晰。对阻尼器进行单轴拉压循环力学试验,研究位移幅值和荷载频率对其输出力-位移曲线以及割线刚度、单位循环耗能量、等效阻尼比和残余位移等力学参数的影响。建立阻尼器的理论模型,数值计算证明该模型能够反映阻尼器的主要滞回性能。编写消能减震结构的地震弹塑性时程分析程序,计算阻尼器对一三层剪切型框架结构的减震控制,结果表明阻尼器能有效抑制结构的位移、层间位移和残余位移,但会增大结构加速度。

An innovative re-centring superelastic shape memory alloy （SMA） damper is proposed. The damper consists of pre-strained SMA strands and regular SMA strands connected to four steel plates. With simple configuration and clear load-transferring mechanism, the damper can present an enhanced energy dissipation capability and a re-centring capability. Cyclic uniaxial tension-compression tests on the dampers are performed in order to assess the influences of the displacement amplitudes and the loading rates on the force-displacement curve and the mechanical parameters, such as the secant stiffness, the per-cycle energy dissipation, the equivalent damping ratio and the residual displacement. A theoretical model of the damper is proposed. The numerical simulation results prove that the model can reflect the main hysteretic behaviors of the dampers. Seismic nonlinear time history analysis program of the damped structure is developed and the seismic responses of a three-story shear-type frame with the SMA damper are calculated. The results show that the damper is effective in controlling the displacement, the inter-story displacement and the residual displacement of the structure, but can increase the acceleration of the structure.