Abstract: Shape memory alloy (SMA) is noticed for its special thermomechanical properties in the research on smart structural actuator system. SMA torsion actuator is made up of nickel-tit- anium alloy wire and a thin-walled tube, in which plastically elongated wire is wound and pasted on a tube with a certain angle referenced to the generatrix of the tube. SMA torsion actuator can yield torsion deformation and moment, which may provide new ideas for wing control system design. SMA wire wound angle is an important parameter that affects actuator primary performances. For actuators with SMA wire wound angles of 40°, 45°, 55°, 60° and 75°, the experimental curves of temperature-wound angle-torsion angle and torque are obtained under free, fixed and flexible-restricted conditions. Results show that actuator, with wound angle of 60°, can produce the maximum torsion angle and the maximum moment. The research is of important value to the investigation of mechanical model and structural parameter optimization of SMA torsion actuators.

Key words: Experimental research, Primary performance, SMA torsion actuator, Wound angle of SMA wire