【作者】 熊九郎；

【导师】 林萍华；

【作者基本信息】 东南大学 ， 材料加工工程， 2006， 博士

【摘要】 为充分发挥SMA的高阻尼特性,制作高性能的新型阻尼器,本文研究了热处理、加载条件和预应变对SMA的迟滞耗能性能的影响规律以及其迟滞耗能性能与振动响应特性的基本关系,在此基础上研制了新型单、双面TiNi SMA环阻尼器,并对其阻尼性能进行了研究。实验研究所确定的热处理制度,可使富镍TiNi SMA(成分为Ti-50.9at%Ni)获得饱满的迟滞环。通过SMA的循环加载实验,以及SMA丝材、载荷和附加弹簧组成的单自由度系统中SMA振动响应特性的理论分析发现,选择恰当的应变幅值和预应变量,优化阻尼器中SMA的迟滞环形状均有利于充分利用SMA的高阻尼性能,但附加弹簧抑制SMA高阻尼性能的发挥。在循环载荷作用下无约束时TiNi SMA环难以消耗能量,阻尼性能差,且承载能力低,但是将其应用于阻尼器中,由于挡板对合金环的约束作用改变了环内的应力大小和分布,单面TiNi SMA环阻尼器不仅具有较好的阻尼性能,且承载能力和抗过载能力高。单面TiNi SMA环阻尼器的静态阻尼性能与合金环层数、横向预变形以及位移幅值密切相关,增加合金环层数能够提高其承载能力和循环载荷作用下的能耗,但阻尼性能未改善;单层环、小位移时,适当的横向预变形能在一定程度上改善其阻尼性能,但随着位移幅值和合金环层数的增加,横向预变形对其阻尼性能的影响逐渐趋于不利;增加位移幅值不仅能提高其阻尼性能,且会改变迟滞环形状,大位移时迟滞环为三角形,能够使SMA在单面TiNi SMA环阻尼器中充分发挥其性能优势。对单面TiNi SMA环阻尼器进行了结构优化,研制出了双面环阻尼器,通过振动台实验测试了其振动响应特性,发现双面环阻尼器具有较复杂的振动响应变化规律,不同于单自由度系统。加入马氏体态SMA环可提高低频段(0~8Hz)的减振能力,并且小载荷作用下多层环夹有马氏体态SMA环或大载荷作用下SMA环全为奥氏体态时,双面TiNi SMA环阻尼器在0~40Hz整个测试频率范围内具有良好的振动响应特性,可充分发挥SMA的高阻尼特性,另外,增加合金环层数和纵向预变形能有效改善其减振效果。更多还原

【Abstract】 In order to fabricate novel dampers with outstanding performances by sufficiently exerting the high damping capacity of shape memory alloy (SMA), the influences of heat-treatment, loading condition and pre-strain on the hysteretic characteristics of TiNi SMA and the relationships between its hysteretic properties and its vibration characteristics were investigated in this paper. Base on above studies, two types of TiNi SMA ring dampers named as single-direction damper and double-direction damper were designed, and their damping capacities were investigated.The heat-treatment technics optimized by the experimental investigations can make Ni-rich SMA (Ti-50.9at%Ni) possess an ideal hysteresis loop. By the cycle loading test and the theoretic analysis of the vibration characteristics of SMA in the single degree of freedom (SDOF) vibration system consisting of SMA wire, load and accessional spring, it was found that the high damping capacity of SMA can be sufficiently utilized if the strain amplitude and the pre-strain were chosen properly, and the hysteresis loop shape of SMA in the damper was optimized, but it was restrained by the accessional spring.Under the cycle loading, the TiNi SMA rings without restriction can hardly dissipate the energy, and its damping capacity and load-bearing ability are low. However, when the TiNi SMA rings are used in the single-direction damper, the damper possessed a good damping capacity, load-bearing ability and an ability to withstand overloading because the restriction of the baffle could change the magnitude and distribution of the internal stress in the SMA rings.The static damping capacity of the single-direction TiNi SMA ring damper was extraordinarily related to the number of SMA rings, the horizontal pre-deformation and the displacement amplitude. With increasing the number of the rings, its load-bearing ability and energy loss under cycle loading were increased, but its damping capacity was not improved. A proper horizontal pre-deformation can increase the damping capacity of the damper with single SMA ring at small displacement, but as the number of rings and the displacement increasing, the horizontal pre-deformation would decrease its damping capacity. With the displacement amplitude increasing, not only the damping capacity was improved, but also the shape of hysteresis loop was changed. When the displacement amplitude was large enough, the hysteresis loop was changed into the triangle shape, which can sufficiently exert the high damping capacity of SMA in the single-direction TiNi SMA ring damper.Finally, based on optimizing the configuration of the single-direction ring damper, a double-direction TiNi SMA ring damper was designed, and its vibration characteristics was investigated. The results indicated that the vibration characteristics of the double-direction更多还原