形状记忆金属自复位钢框架抗震性能分析

Seismic Behavior Analysis of Self-centering Steel Frame with Shape Memory Alloy

通过将强震时钢框架结构可能发生较大塑性变形区域的材料更换成形状记忆金属(Shape Memory Alloy,简称SMA)板件制成一种新型SMA自复位钢框架。为考察SMA更换区域对结构滞回性能及复位效果的影响,设计6个单跨2层的SMA自复位钢框架,采用ANSYS软件建立全实体模型进行滞回性能分析。分析表明将结构底层柱根部、顶层节点域及除顶层外的梁塑性铰区材料更换成SMA板,结构滞回曲线呈明显的旗帜状,结构残余变形极小、复位效果最好、经济性最优,但耗能能力较传统结构降低较大。此外,根据优化结果设计4层3跨SMA自复位钢框架,采用ANSYS软件建立多尺度有限元模型,进行罕遇地震作用下的弹塑性时程分析。结果表明优化后的结构较传统结构抗侧刚度小、侧向变形大,但震后结构残余变形极小,结构自复位效果较好。

An innovative self-centering steel frame is presented through using shape memory alloy （SMA） plates to fabricate the large plastic deformation zone of＇the steel structure under strong earthquakes. In order to investigate the influence of SMA replacement zone on the hysteretic character and the self-centering effect of the structure, six one-bay two-story self-centering steel frames are designed for the hysteretic character analysis of the full solid model by using ANSYS software. It is indicated that, if materials of the bottom column root, the top joint field and the beam plastic zone except for the top floor are replaced by SMA plates, the hysteretic curves are banner type, the residual displacements are very small, and the self-centering effect of the structure is the best, the economy of the structure is optimal, yet the energy dissipation capacity is lower than the traditional structure. In addition, four-story three-bay SMA self-centering steel frames are designed according to optimization results, and the multi scale finite element model is established by ANSYS software for the elastoplastic dynamics time-history analysis under rare earthquakes. The results show that, compared the optimized structure with the traditional structure, the lateral stiffness is small, the lateral deformation is large, but the residual deformation is very small after earthquake and the self-centering effect of the structure is better.