| Research Abstract |
The pseudoelastic property and shape memory property which are the main features of shape memory alloy were investigated by the precise and systematic experiments under the general thermomechanical loading conditions. That is, the combined loads of axial force and torque were applied to the thin-walled tubular specimen made of shape memory alloy under the change of temperature, and the strain responses were measured for various kinds of thermo-mechanical loading paths. In the results, new interesting behaviors of shape memory alloy could be found, which are useful for engineering/industrial applications of shape memory alloy. For examples, shape memory alloy deforms in three-dimensional way, and this deformation is repeatable, and controlable. That is, the shape memory alloy may be applicable for the element for three-dimesional positioning device. In this case, it is not necessary to employ a complex system composed of many mumber of shape memory wires for the design of robot's arm which behaves smoothly in three-dimensional way. Also, these behaviors were analyzed from microscopic point of view. Finally, a set of constitutive equations for these behaviors was formulated, which are quite useful for the design of actuator, sensor, robots arm, positioning device and so on, by using the shape memory alloy.
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