SMA滑动摩擦阻尼器的数值模拟及参数分析

该文将超弹性形状记忆合金(shape memory alloy,SMA)螺栓和摩擦斜面结合，提出一种SMA滑动摩擦阻尼器(SMA slip friction damper,SMASFD)。介绍了SMASFD的基本构造和工作原理，给出描述滞回行为的理论公式，开展了概念验证试验，建立了三维实体单元有限元模型。试验数据和分析结果均表明，采用合理设计的斜面倾角和摩擦系数，阻尼器可展示出“旗帜形”滞回曲线，拥有良好的耗能能力和优越的自复位能力，并且理论公式和模拟结果均与试验数据吻合良好。基于已经验证的有限元模型，建立了6个额外的有限元模型进行参数分析，关键参数包括斜面倾角、摩擦系数和SMA螺栓的预紧力。参数分析结果表明：阻尼器的非线性变形集中于SMA螺栓内，其他部件保持弹性；增大斜面倾角可提高阻尼器的强度、割线刚度和耗能能力；当接触面间的摩擦系数较大时，阻尼器的耗能能力得到提高，但是超过上限值会导致阻尼器无法自复位；对SMA螺栓施加预紧力可提高阻尼器的初始刚度和割线刚度，但是会降低阻尼器的最大变形能力。

NUMERICAL SIMULATION AND PARAMETRIC STUDY OF SHAPE MEMORY ALLOY SLIP FRICTION DAMPERS

A novel self-centering shape memory alloy slip friction damper (SMASFD) is proposed by combining shape memory alloy (SMA) bolts and friction interfaces of grooved plates. This paper introduces the configuration and working mechanism, the theoretical equations, the proof-of-concept test, and a finite element (FE) model of the damper. The result shows that the damper with an appropriate design of the groove angle and friction coefficient has flag-shaped hysteresis, which indicates good energy dissipation capacity and excellent self-centering capability. Both the analytical prediction and the simulation results agree well with the experimental data. A parametric study is carried out based on the verified FE model. Six additional models are established. The key parameters include the groove angle, friction coefficient and preloading of SMA bolts. The results indicate that: the nonlinear deformation is concentrated in the SMA bolts, and the other components remain elastic; increasing the groove angle will increase the strength capacity, secant stiffness and energy dissipation; the energy dissipation capacity increases with the increase of the friction coefficient, but the self-centering capacity will be lost if the friction coefficient exceeds the upper limit; preloading the SMA bolts enhances the initial stiffness and secant stiffness, but it reduces the deformation capacity of the damper.