形状记忆合金-摩擦复合阻尼器力学性能研究

提出一种新型形状记忆合金（shape memory alloy，简称SMA）-摩擦复合阻尼器。该阻尼器由超弹性SMA单元和高耗能摩擦单元串联而成，通过控制摩擦单元的摩擦力大于SMA单元的最大输出力，可实现自动调节耗能单元工作状态的功能，即：较小荷载作用下，仅SMA单元工作，消耗能量少，具有自复位功能；较大荷载作用下，SMA单元和摩擦单元依次工作，消耗大量能量，具有一定的变形回复能力。对阻尼器进行拉压循环力学试验，研究了位移幅值、加载频率和扭矩对其输出力-位移曲线以及摩擦力、割线刚度、单位循环耗能量、等效阻尼比、残余位移等力学参数的影响。将基于Graesser本构模型基础上的SMA单元力学模型和摩擦单元的理想刚塑性模型串联，建立了阻尼器的力学模型；数值模拟结果与试验结果吻合较好，证明了该力学模型的正确性。

Investigation on mechanical behavior of innovative shape memory alloy-friction damper

An innovative shape memory alloy (SMA)-friction damper is proposed. The damper consists of the superelastic SMA element and the friction element in series. Given that the friction force provided by the friction element is greater than the maximum output force generated by the SMA element, the damper can adjust the working status of the two elements automatically, i.e. when the load is smaller, only the SMA element functions, generating a low energy dissipation but an excellent self-centering capacity; when the load is larger, the SMA element and the friction element work in turn, presenting a considerable energy dissipation but a moderate residual displacement. Cyclic tension-compression mechanical tests on the damper were performed in order to assess the influences of the strain amplitude, the loading frequency and the torque on the force-displacement curve and the mechanical parameters, such as the friction force, the secant stiffness, the energy dissipation per cycle, the equivalent damping ratio and the residual displacement. Combining the mechanical model of the SMA element which is based on the Graesser’s constitutive model and the ideal rigid-plastic model of the friction element, the mechanical model of the damper was set up. The numerical simulation results agree well with the test data，which proves that the proposed model is valid.