Actuation performance of shape memory alloy friction-spun yarns.

This paper reports study on the determination of the actuation performance of shape memory alloy (SMA) friction-spun yarns (SMA FSY). Thin SMA actuator wire has been spun with 100% cotton fibres into the core of the friction spun yarn structure using DREF 3000 friction spinning. The delivery speed (m/min) an suction pressure (rpm) are varied, while the spinning drum speed as well as the core-sheath ratio are kept constant during production. The SMA FSY has been electrically heated using a customized instrument and the results are reported as the work done (potential energy) and output power (Watt) needed to lift the load (constant weight) from staticcondition. The actuation performances of the SMA FSY are compared with SMA wires actuation performance without sheath. The changes in spinning parameters show different actuation performance of SMA FSY, which is measured as the height to lift the load and the time taken for the SMA core to return to the pre-determined shape. The cohesion between the sheath and the wire may have contributed to the difference in the actuation performance based on the internal friction test. [ABSTRACT FROM AUTHOR]