Theoretical and experimental studies of torsion deformation of a thin-walled tube with wound and pasted shape memory alloy wires

Restrained shape memory alloy (SMA) wires, as actuators, are wound and pasted onto the outside surface of a thin-walled circular tube at angle of alpha degrees with respect to the tube axis. Upon heating the wires, the martensitic residual strain will be restored, and the large recovery forces induced so that the tube will deform. This paper presents a mechanical model of a thin-walled tube, pasted with actuators (SMA wires), the analyses of the mixed deformation, of compression and torsion, of the tube and the relation between the angle of twist and the temperature in a temperature cycle. The theoretical predictions are validated with static experiments.