Abstract
The authors proposed a sandwich structure that consists of a shape memory alloy (SMA) honeycomb core and carbon
fiber reinforced plastic (CFRP) skins as a lightweight geometric-variable structure. This method has the better ability to
bend skins with high in-plane stiffness, because the SMA honeycomb core generates a recovery-shear-force and applies
the force uniformly to the skins. Hence, although this sandwich beam is really lightweight and has a moderate specific
bending stiffness, the beam can be bent by raising the temperature. The honeycomb core was made of thin Ti-Ni SMA
foils, and skins were thin unidirectional CFRP laminates. Pre-shear-strain was applied to the SMA honeycomb core, and
the both ends of the two skins were fixed. When the beam was heated, it was bent upward taking the form of a sigmoid
curve. Furthermore, it was verified that the beam was able to generate the sufficient actuation force. Then, when the
specimen was cooled down to the room temperature, the specimen returned to the straight beam again. Hence the twoway
actuation is possible by heating and cooling. Also the mechanism of this bending deformation could be clarified by
a numerical simulation using the finite element method.
