Characterization of shape memory alloy wires integrated into lightweight structures

The integration of smart materials into polymer compounds is one promising technology to improve lightweight structures by enhancing their intrinsic range of functions [1]. Integration of piezoelectric fiber composites [2], dielectric elastomer actuators [3], or wires made of thermal shape memory alloys (SMA) into a thermoplastic polymer offers great potential due to their sensoric and actuatoric behavior. In this study we focus on the integration of SMA wires. This paper presents experimental and theoretical results on functional fatigue, the relaxation behavior and the adhesive strength to polymers of uniaxially loaded thermal SMA actuator wires. Our combined study shows that these considerably different aspects and extensive experimental work is required to develop reliable morphing polymer compounds. An exemplary structure is shown in Fig. 1 that bends because of the asymmetric thickness above and below the layer of the SMA wires when activated.