パッシブ防振システム用板状Ti-Ni形状記憶合金素子の座屈後特性におよぼす熱処理温度の効果

抄録

Ti-Ni shape memory alloy (SMA) system is well known as a functional material which shows the shape memory effect and superelasticity. It is reported that the tape-shaped Ti-Ni SMA shows the negative stiffness during post-buckling deformation, the tape-shaped Ti-Ni SMA is expected to be an effective vibration isolator for small devices. On the oyher hands, the tape-shaped Ti-Ni SMA does not show the negative stiffness during post-buckling deformation depending on \ the variation of heat-treatment and a environmental temperature condition. Then, in this study, the effect of heat-treatment temperature on the post-buckling behavior of the tape-shaped Ti-Ni shape memory alloy is investigated. The chemical composition of alloy used in this study is Ti-50.2at%Ni. The specimen is a liner tape-shaped 0.45mm in thickness, 7.0mm in width and 30mm in length. The sample is memorized to have a liner shape by heat-treatment. The heat-treatment temperature is varied from 573K to 723K for 3.6ks. The mechanical properties and buckling characteristic of heat-treated specimens are measured by the tensile-test and buckling-test at a constant temperature varide from 303K to 323K. Results of the experiments, it is clear that the tape-shaped Ti-Ni specimen shows negative stiffness during post-buckling deformation at the temperature around the Af temperature.