Modeling and Analysis of SMA-Based Adaptive Structures

Abstract: The application of shape memory alloys (SMA) as actuators in smart structures is a quickly developing field. The particular focus of this paper is on the aspects of modeling and simulation of adaptive structures with integrated SMAs using the finite element method (FEM). A number of generic SMA actuator wire/elastic beam systems are presented first to illustrate the different ways of implementation of SMA models into COMSOL. Finally, a first step towards the simulation of an SMA-based flapping Micro Aerial Vehicle (MAV) is presented. The actuation of a typical bio-inspired humerus-radius system is effected by means of micro-scale actuator wires performing like metal muscles when heated. In addition, the elbow is modeled as a flexible hinge using superelastic SMA wires. This system serves as is the first step towards the design of a flapping wing of a man-made bat, which might propel the next generation MAV. In this bio-inspired bone-joint-system, the humerus and radius were modeled as standard elastic beams. Shape memory alloys were applied in two different ways: one is an SMA wire in the martensite phase, the other is an SMA beam in the austenite phase. The SMA wires function as muscles to actuate the bio-system due to contraction upon electric heating. The SMA beams function as flexible joints due to their superelastic character. In this paper, the modeling and simulation of an active structure, which is actuated by SMAs will be presented