SMA节点自回复性能的有限元研究

Numerical study of self-centering performance of shape memory alloy( SMA) connections

已有研究显示,角钢尺寸对SMA节点滞回耗能和自回复性能有很大的影响,施加初始预应变可以显著改善节点小变形下的力学行为。为了进一步讨论螺杆预应变和角钢尺寸对SMA节点自回复性能的影响,分别以螺杆预应变、角钢承载力比为参数设计了一系列SMA节点,采用ANSYS14.5对上述节点进行有限元模拟,并分别从刚度、强度、延性、滞回耗能和自回复性能等五个方面讨论螺杆预应变和角钢承载力比对SMA节点抗震性能的影响。有限元结果表明:SMA节点残余层间位移角和滞回耗能量均与角钢承载力比近似呈线性关系;施加初始预应变可以明显改善节点初始刚度、提高节点极限承载力和自回复性能,但不能保证节点在大层间位移角下的延性。

Previous research shows angle size had much influence on hysteretic energy dissipation and self-centering performance of SMA connections and applying pre-strain could improve mechanical behavior of SMA connections at small story-drift. A series of SMA connections were designed with respect to pre-strain of SMA bars and ratio of angle capacity to further discuss the effect of these two factors on seismic performance of SMA connections. FEM analysis software ANSYS14. 5 was adopted to establish and simulate SMA connections. Then,the connections were discussed from stiffness,strength,ductility,hysteretic energy dissipation and self-centering capacity respectively. Numerical results indicate both residual story-drift and hysteretic energy dissipation of SMA connections changed nearly linearly with the ratio of angle capacity. In addition,applying initial pre-strain could improve connection stiffness significantly; it could promote ultimate capacity and self-centering performance as well. But,it couldn't guarantee connection ductility at large story-drift.