SMA自复位转动摩擦阻尼器的滞回特性与参数影响分析

Hysteresis characteristics and parameter influence analysis of SMA self-centering rotational friction damper

摘要:

为减少结构在地震作用下的残余变形,本文提出了一种基于形状记忆合金（shape memory alloy,SMA）螺栓的自复位转动摩擦阻尼器（shape memory alloy self-centering rotary friction damper,SMA-SRFD）,介绍了其基本构造及工作原理,开展了SMA螺栓材性实验,对螺栓及SMA-SRFD的受力性能进行了理论分析,并与有限元分析结果进行了对比,验证所采用理论公式的准确性；建立SMA-SRFD三维有限元模型,并选取旋转子中摩擦斜面倾角、摩擦系数及SMA螺栓预紧力为变量进行了参数分析。结果表明:SMA螺栓的应力应变曲线呈典型的“旗帜”形,具有良好的耗能及自复位能力；SMA-SRFD理论分析与数值模拟结果吻合,二者均可准确反映阻尼器的受力过程；增大斜面倾角,会提升SMA-SRFD的承载能力及等效刚度,但阻尼器耗能及阻尼比降低；提高接触面之间的摩擦系数,SMA-SRFD的耗能、等效刚度及等效阻尼比均随之增加,自复位能力减弱；随着SMA螺栓预紧力的增加,SMA-SRFD的最大承载力基本相同,而变形量会略有减小,此外,对SMA螺栓施加不同的预紧力,阻尼器的滞回性能无显著变化。

Abstract:

To reduce the residual deformation of structures under seismic loading, a self-centering rotary friction damper (SMA-SRFD) based on shape memory alloy (SMA) bolts was proposed. The basic structure and working principle of the damper were introduced. Material property tests of SMA bolts were conducted, and theoretical analysis of the force performance of the bolts and SMA-SRFD was carried out. The results were compared with those from finite element analysis to verify the accuracy of the theoretical formulas used. A three-dimensional finite element model of the SMA-SRFD was established, and a parametric analysis was performed with the rotation angle of the frictional inclined plane, the friction coefficient, and the pre-tension of the SMA bolts as variables. The results show that the stress-strain curve of the SMA bolt exhibits a typical “flag” shape, indicating good energy dissipation and self-centering capabilities. The results of theoretical analysis and numerical simulation of the SMA-SRFD are consistent, both accurately reflecting the force process of the damper. Increasing the inclination angle of the inclined plane enhances the load-bearing capacity and equivalent stiffness of the SMA-SRFD, but the energy dissipation and damping ratio decrease. By increasing the coefficient of friction between the contact surfaces, the energy dissipation, equivalent stiffness, and equivalent damping ratio of the SMA-SRFD all increase, while the self-centering capability weakens. As the pre-tension of the SMA bolts increases, the maximum load-bearing capacity of the SMA-SRFD remains essentially the same, while the deformation decreases slightly. Moreover, the different pre-tensions to the SMA bolts does not significantly change the hysteresis performance of the damper.