Effect of shape memory alloy actuator geometric non-linearity and thermomechanical coupling on the response of morphing structures

The response of adaptive structures entailing shape memory alloy actuators is investigated both numerically and experimentally in this work. Emphasis is placed on the inclusion of large displacements and rotations, as well as thermomechanical coupling in the simulation of the shape memory alloy actuators. Reduced multi-field beam finite element models for shape memory alloy actuators, encompassing a co-rotational formulation for large displacements and capability to provide the thermomechanically coupled transient response, are briefly overviewed. Prototypes of two adaptive structure configurations are developed, experimentally characterized, and numerically modeled. The measured response of the two prototypes is correlated with respective numerical results that consider both the geometric non-linearity and the thermomechanical coupling of the shape memory alloy actuators. Hence, the influence of these two effects on the predicted response of both the actuator and the adaptive structure is demonstrated. The results quantify also the interactions between geometric non-linearity and thermomechanical coupling terms. As it is shown, better agreement with experimental data is obtained when considering both effects.