形状记忆合金回复性能研究及其在混凝土梁裂缝修复中的应用

Recovery performance of shape memory alloy and its application in repairing cracks of concrete beams

为探讨形状记忆合金(SMA)对钢筋混凝土梁裂缝的修复效果,进行了SMA丝的回复性能试验,结果表明:施加恒定电流得到的SMA丝的回复应力大于施加台阶式电流;当初始应变小于最大回复应变时,SMA的回复应力随其初始应变的增大而增大;当电流激励产生的温度过高时,SMA材料发生软化导致回复应力下降。此外,在试验的基础上,将SMA丝的受限回复应力等效为偏心荷载和钢筋的初始应力,对SMA智能混凝土梁进行了有限元分析,证明这两种等效方法简便可行;同时还探讨了SM A丝的不同直径、根数和初始应变对混凝土梁的裂缝修复效果的影响。

For investigating the effect of shape memory alloy（ SMA） for repairing cracks in reinforced concrete beams,the reply performance of SMA was studied. The results showthat the recovery stress of SMA with applying constant current is greater than applying stepped current. And when the initial strain is less than the maximum recovery strain,the recovery stress increase with the increase of initial strain. But the recovery stress decrease due to the softened material if temperature is too high. Then,based on the experiment,a smart concrete beam embedding with SMA was analyzed with the method that the recovery stress of SMA was equivalent to the eccentric load and the initial stress of steel. And the method was proved to be simple and feasible. Moreover,the effect of SMA for repairing cracks in reinforced concrete beams with different diameters,roots and initial strains has been researched.