Development and experimental consideration of SMA/CFRP actuator for vibration control

Abstract

One of the significant advantages of shape memory alloy (SMA) is its large recovery force generated by phase transition at specific temperature when initial deformation had been applied. Because of manufacturing and processing difficulties, SMA materials have been often used by the way of wires embedded in a variety of matrices when they are applied as actuators. Its great advantage, i.e. large generated force and displacement, raises, on the other hand, a problem at the SMA/matrix interface. The purpose of this paper is a proposition of a safety SMA actuator form with which no debonding occurs even when the maximum shear stress is generated by recovery force in SMA wires. Superior interfacial strength was obtained by the way of embedding SMA wires, memorized to sinusoidal curve shape, in the supported parts of the actuator. It provides holding stress over the fracture stress of SMA wires. An actuator form with eight SMA wires semi-embedded in two supporting parts made by CFRP was, thus, proposed. Besides, there exist again some difficulties to use SMA materials as active actuators, for example, its slow response speed. Particular driving system with cooling system is constructed in consideration with characteristics of SMA materials. The first and the second mode vibration suppressions of 2 m beam were carried out to evaluate the efficiency of the proposed actuator, mounted on one side closed to the clamping edge, as an active actuator, and the system. Control effect on beam structure is, then, demonstrated experimentally even for around 5 Hz.