Characteristics of energy storage and dissipation in TiNi shape memory alloy
Characteristics of energy storage and dissipation in TiNi shape memory alloy
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DOI：
10.1016/j.stam.2005.07.008
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发表时间：
2005-11-01
影响因子：
5.5
通讯作者：
Tobushi, H
中科院分区：
文献类型：
--
作者：
Pieczyska, E;Gadaj, S;Tobushi, H
根据TiNi形状记忆合金在不同热机械载荷条件下的超弹性特性，实验研究了TiNi形状记忆合金的储能和耗能特性。研究了应变速率、循环加载和温控条件对材料储能和耗能特性的影响。观察了材料表面的温度变化，阐明了温度变化对材料特性的影响。所获得的结果可概括如下。(1)在低应变率下，由于加载和卸载过程中的马氏体相变和反向相变，应力-应变曲线上出现应力平台。在高应变率的情况下，加载和卸载过程中，应力-应变曲线在相变区的斜率较大。单位体积的可恢复应变能与温度成正比增加，但单位体积耗散功与温度的关系不大。在低应变率情况下，可恢复应变能和耗散功与应变率和温控条件无关。(2)在高应变率的情况下，温控引导条件下的可恢复应变能密度随应变率的增加而减小，耗散功密度随应变率的增加而增大，而非温控条件下的可恢复应变能密度增大，耗散功密度减小。在非控温条件下，由于马氏体相变，温度变化很大，因此储能和耗能特性与温控条件下不同。(3)在循环加载的情况下，可恢复应变能和耗散功在前20周都有所下降，但此后变化不大。(4)在设计形状记忆合金元件时，应考虑应变率、循环载荷和环境对储能和耗能特性的影响。(C)2005爱思唯尔有限公司。保留所有权利。
The characteristics of energy storage and dissipation in TiNi shape memory alloys were investigated experimentally based on the superelastic properties under various thermomechanical loading conditions. The influence of strain rate, cyclic loading and temperature-controlled condition on the characteristics of energy storage and dissipation of the material was investigated. Temperature on the surface of the material was observed and the influence of variation in temperature on the characteristics was clarified. The results obtained can be summarized as follows. (1) In the case of low strain rate, the stress plateaus appear on the stress-strain curves due to the martensitic transformation and the reverse transformation during loading and unloading. In the case of high strain rate, the slopes of the stress-strain curves are steep in the phase-transformation regions during loading and unloading. The recoverable strain energy per unit volume increases in proportion to temperature, but the dissipated work per unit volume depends slightly on temperature. In the case of low strain rate, the recoverable strain energy and dissipated work do not depend on both strain rate and the temperature-control led condition. (2) In the case of high strain rate, while the recoverable strain energy density decreases and dissipated work density increases in proportion to strain rate under the temperature-control led condition, the recoverable strain energy density increases and dissipated work density decreases under the temperature-uncontrolled condition. In the case of the temperature-uncontrolled condition, temperature varies significantly due to the martensitic transformation and therefore the characteristics of energy storage and dissipation differ from these under the temperature-controlled condition. (3) In the case of cyclic loading, both the recoverable strain energy and dissipated work decrease in the early 20 cycles, but change slightly thereafter. (4) The influence of strain rate, cyclic loading and the environment on the characteristics of energy storage and dissipation is important to be considered in the design of shape memory alloy elements. (C) 2005 Elsevier Ltd. All rights reserved.