一种新型SMA阻尼器的试验和数值模拟研究

A type of shape memory alloy damper:design,experiment and numerical simulation

利用超弹性SMA丝的耗能能力和自复位能力，提出了一种新型的SMA阻尼器，试验研究了该阻尼器在循环荷载作用下不同位移幅值、不同加载频率和不同初始位移条件下的力学性能，并通过建立的理论模型对阻尼器的力学性能进行了数值模拟。研究结果表明：该新型SMA阻尼器在循环荷载作用下形成稳定的滞回曲线，具有良好的耗能能力和自复位能力;阻尼器的性能可通过调节超弹性SMA丝的初始应变而改变，以满足工程的需要;动力荷载（0．5～2Hz）频率对阻尼器的耗能能力和等效阻尼比影响不大，而恢复力和割线刚度随频率增加而略微增大;数值模拟结果和试验结果吻合较好，建立的理论模型可以对SMA阻尼器进行理论分析。

Shape memory alloy （SMAs） are a kind of new smart material, possessing unique behaviors, such as shape memory effect, superelasticity and high damping characteristic. These properties enable SMAs to be ideal candidate for the design of the energy dissipation system in civil engineering. In this paper, a new type of SMA damper was proposed by utilizing the energy dissipating and reeentring features of superelastic SMA. Cyclic tests on the damper model were carried out in order to investigate the mechanical behaviors as a function of pre-displacement, displacement amplitude and loading frequency. The numerical simulation for the mechanical behavior of the damper was performed by means of the developed constitutive model of SMA. The research results show that the innovative SMA damper has both the energy dissipating and reeentring features with the hysteretic loop under cyclic loading-unloading. The hysteretic behaviors of the damper can be modified to best fit the needs for passive structural control applications by adjusting the pre-tension of the Nitinol wires and are not sensitive to frequencies greater than 0. 5Ha. The numerical results with the developed constitutive model agree well with the experimental data, which verifies that the model can be used to simulate the behavior of the damper.