Effect of the curvature of the cross-section on buckling characteristics of convex-tape-shaped Cu-Al-Mn shape memory alloy elements

Abstract

When an elongated columnar shape memory alloy (SMA) element buckles, in some cases it exhibits negative stiffness. This post-buckling negative stiffness can be repeatedly used as SMAs can recover their shape. This property has potential application to passive vibration isolation devices. A previous study on the behavior of convex-tape-shaped Ti-Ni SMA elements found that their properties are superior to those of normal flat-tape-shaped SMA elements. However, a Ti-Ni SMA has a high dependence on environmental temperature. Therefore, this study investigates the effect of cross-sectional curvature on the buckling characteristics of convex-tape-shaped Cu-Al-Mn SMA elements, whose shape memory and mechanical properties are less dependent on environmental temperature than those of a Ti-Ni SMA, using the three-dimensional finite element method and a buckling test. The results show that the post-buckling negative stiffness increases with increasing cross-sectional curvature. This tendency is similar to that for a Ti-Ni SMA, indicating that the buckling characteristics of a Cu-Al-Mn SMA can be designed using methods for a Ti-Ni SMA. Moreover, the lower temperature dependence of a Cu-Al-Mn SMA compared to that of a Ti-Ni SMA makes a Cu-Al-Mn SMA more suitable as a material for vibration isolators.

Keywords

• shape memory alloy (sma)
• ti-ni
• cu-al-mn
• buckling
• negative stiffness
• passive vibration isolation device