利用形状记忆合金(Shape Memory Alloy,简称SMA)丝的超弹性,提出了一种具有复位功能的SMA阻尼器.在SMA丝的Graesser本构模型基础上,建立了SMA阻尼器恢复力的常规模型,进而提出了其简化模型.采用随机等价线性化法建立了SMA阻尼器控制的单自由度结构在高斯白噪声激励下的随机振动理论.通过一算例,考虑不同激励谱密度和结构阻尼比:比较了随机振动理论和蒙特卡罗(Monte Carlo)模拟法计算的结构振动响应,证明了随机振动理论的有效性;说明了SMA阻尼器能提高结构的刚度和阻尼比,因而可有效抑制结构的振动.
Using superelastic shape memory alloy (SMA) wire,a re-centring SMA damper is presented.Based on the Graesser's constitutive model of SMA wire,the conventional restoring force model of the SMA damper is suggested,further,a simplified restoring force model is put forward.Using a stochastic e quivalent linearization method,the random vibration theory of a single-degree-of-freedom structure with the SMA damper subjected to the Gaussian white noise excitation is set up.Numerical simulations are carried out,taking various excitations' spectrum densities and damping ratios of the structure into account.Comparisons of the vibration responses of the SMA-damped structure between the random vibration theory and the Monte Carlo simulation method validate the random vibration theory.The simulations also show that the SMA damper can decrease the structural vibration effectively,which is attributed to its capabilities of increasing the stiffness and the damping ratio of the structure.