SMA弹簧—摩擦支座的滞回性能研究

Hysteretic performance of a SMA spring-friction bearing

研究一种新型形状记忆合金弹簧-摩擦支座(SMA Spring-Friction Bearing,SFB)的滞回性能。首先,研制了可用于SFB的大尺寸超弹性NiTi记忆合金(NiTi SMA)螺旋弹簧。在此基础上,加工制作了SFB试件实物模型,对其进行了拟静力试验研究。考察了竖向压力、位移幅值和加载频率对SFB恢复力-位移曲线以及等效刚度、单位循环耗能、等效阻尼比和等效动摩擦因数的影响。最后,将SMA螺旋弹簧恢复力模型和摩擦力模型相叠加,建立了SFB的恢复力模型,利用该模型进行了数值模拟。研究结果表明:SFB可提供饱满的滞回曲线,耗能能力较强,且具有一定的复位能力;数值结果与试验结果吻合较好,验证了SFB恢复力模型的正确性。

Here,hysteretic performance of a new type of isolator called shape memory alloy （SMA）spring-friction bearing （SFB）was studied both experimentally and theoretically.Firstly,large scale superelastic NiTi SMA helical springs used for SFB were developed.Then,a SFB specimen was designed and fabricated.Secondly,the quasi-static tests for SFB under different loading conditions were conducted to study the influences of vertical pressure,displacement amplitude and loading frequency on SFB hysteretic curves and mechanical parameters,such as,equivalent stiffness, energy dissipation per cycle,equivalent damping ratio and equivalent kinetic friction coefficient.Finally,combining the restoring force model of SMA spring and the model of friction force,a simplified restoring force model for SFB was established and this model was employed to simulate the hysteretic behavior of the proposed isolation device.The results showed that SFB provides full hysteretic curves,an excellent energy dissipation capacity and a certain re-centering ability;moreover,the numerical results agree well with those of tests to verify the correctness of the restoring force model for SFB.