Numerical and experimental analysis of shape memory alloy-polymer composite for aerodynamic morphing applications

Shape memory alloy (SMA)-polymer composites offer promising opportunities for aerodynamic morphing structures in automotive applications, but face significant challenges related to adhesion at the SMA-polymer interface, thermomechanical stresses during activation, and delamination under repeated actuation cycles. Predicting the mechanical response of SMAs under complex fluid-structure interaction (FSI) coupling is also complex, lacking experimental validation in the literature. This research addresses these issues by developing a robust multi-material design and fully-coupled FSI modeling approach within COMSOL Multiphysics. Both numerical modeling and experimental tests are employed, with comprehensive multiphysics FSI simulations incorporating thermomechanical SMA constitutive models to predict structural-aerodynamic force interactions. Model validity is established through wind tunnel tests on a thermally activated SMA-polymer composite plate subjected to fluid flows up to 125 km/h to assess aerodynamic influence on deformation. Simulation and experimental results show a very good agreement, with peak deflection discrepancies within 5%. An increased airflow velocity significantly reduces the peak plate deflection by up to 35% at the maximum tested velocity. Furthermore, the FSI model effectively captures the stress distribution within SMA wires, crucial for evaluating structural integrity. This investigation successfully validates the FSI modeling approach for SMA-driven composites, providing insights into their structural performance under aerodynamic loads to optimize the design of SMA-based morphing structures and to guide future research enhancing their durability and functionality.