Papers by Author: Shunichi Hayashi

Abstract: The shape-memory composite belt with a TiNi-SMA wire fiber and a polyurethane-SMP sheet matrix was fabricated. The bending actuation characteristics of the belt were investigated by the thermomechanical tests. Residual deflection obtained by cooling under constant maximum deflection is close to the maximum deflection. The residual deflection disappears by heating under no load. Both the rates of shape fixity and shape recovery are close to 100%. Recovery force which appears by heating under constant residual deflection is 93-94% of the maximum force. The model of bending-spring constant of the shape-memory composite belt is proposed and evaluated based on the experimental data.

Abstract: The influence of the strain-holding conditions on shape recovery and secondary-shape forming was investigated. The results obtained are summarized as follows. (1) If strain is held at holding temperature Th = Tg+20K in a short time, irrecoverable strain starts to appear at the holding time th= 0.5h and strain is not recovered at all at th=8h. In the case of Th = Tg+10K, irrecoverable strain appears in a short holding time if holding strain is large and the rate of secondary-shape forming S is 42% at th=8h. (2) If strain of 50% is held at Th = Tg+10K in a long time, strain becomes not to be recovered and S is 93% at th =12h. In the case of Th = Tg, the increasing rate of S increases if th is longer than 40h. If Th is lower than Tg-10K for th= 72h, strain is recovered perfectly by heating and secondary-shape forming does not appear.

Abstract: The shape-memory composite belt with a TiNi-SMA wire fiber and a polyurethane-SMP sheet matrix was fabricated. The bending actuation characteristics of the belt were investigated by the thermomechanical tests. The results obtained can be summarized as follows. (1) Residual deflection close to the maximum deflection is obtained by cooling under constant maximum deflection. The residual deflection disappears by heating under no load. Both the rate of shape fixity and the rate of shape recovery are close to 100%. (2) Recovery force appears by heating under constant residual deflection. The recovery force is 93-94% of the maximum force. The development of high functionality of shape-memory composite elements is expected by various combinations of SMAs and SMPs.