摘要:
形状记忆合金(Shape Memory Alloy,简记为SMA)是一种新型的智能材料,除了具有形状记忆效应(Shape Memory Effort,简记为SME)外,还拥有相变伪弹性(Pseudo-Elasticity,简记为PE)性能和高阻尼耗散因子的性能.文章基于SMA的相变伪弹性的力学原理,设计并制作了SMA耗能器,并对器件进行了性能测试.结果表明,(1)SMA耗能器具有非常显著的阻尼耗能性能,平均等效粘滞阻尼比最大可达到33.56%,最小也有14%,能较好地满足结构被动耗能振动控制的要求;(2)SMA耗能器的阻尼性能与加载频率有关,在低频加载时阻尼性能较好,但随着加载频率的提高,阻尼性能逐步下降;(3)SMA耗能器的阻尼性能与最大行程的大小有关,当最大行程过小或过大时,其等效粘滞阻尼比较小,当最大行程为极限行程的1/2大小时取得最大等效粘滞阻尼比;(4)在多次循环加载时,器件的应力应变滞回曲线具有整体向上的漂移现象,吻合了其他学者进行的SMA材料试验结果,这一现象的发现提高了此次研究中检测到的试验数据结果的可信度;(5)实验结果与理论分析结果吻合程度较好,表明器件的设计是合理的、加工制作的工艺满足了理论要求.
Abstract:
Shape memory alloy(SMA)is a new smart material. Besides shape memory effect(SME), this material also exhibits pseudo-elasticity(PE)and higher energy dissipation factor. In this paper, SMA damper is designed and made based on PE of SMA, the capability of this damper is tested. The results indicate that:(1)SMA dampers exhibit significant damping capability; the maximum value of the average equivalent viscous damping ratio can reach 33.56%, the minimum value is 14%; it can suit preferably to the passive control of structure vibrations.(2)The damping capability of SMA damper depends on the load frequency; the damping capability is better in lower frequency; the damping capability descends gradually when the load frequency is increased.(3)The damping capability is also dependant upon the stroke of SMA damper; the average equivalent viscous damping ratio is less when the stroke is either too small or too large; the maximum equivalent viscous damping ratio is acquired when the maximum stroke is 1/2 of its limit value.(4)The stress-strain curve of SMA damper shows itself holistic upward excursion when it is loaded cyclically, agreeing with the available test results.(5)The test results conform with the theoretical results very well.
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