Comparative structural evaluation of polymer-based morphing wing ribs using finite element analysis for optimized adaptive aerospace applications

Morphing wing ribs are essential for enabling adaptive aerodynamic performance, reduced fuel consumption, and operational flexibility in low-speed aircraft and UAVs. This study presents a comprehensive structural evaluation of trailing-edge morphing ribs fabricated from five engineering thermoplastics; Nylon, Polycarbonate, Polyethylene, Polypropylene, and Polystyrene across three rib topologies; 50:50, 60:40, 70:30 rigid-to-flexible ratios, three thicknesses; 2.5, 5.0, 7.5 mm, and three prescribed deflection angles; +5°, + 10°, + 15°. A linear-static finite element analysis was conducted in ANSYS Workbench to quantify total deformation, von Mises stress, and safety factor for 135 design configurations. Boundary conditions replicated spar attachment and controlled trailing-edge displacement, with isotropic, linear-elastic material properties applied. A composite performance index, integrating normalized stiffness and safety factor, facilitated comparative ranking of all configurations. Results indicate that rib thickness dominates stiffness, with 7.5 mm ribs showing a 200–220% increase over 2.5 mm ribs. Safety factor is strongly constrained by deflection and thickness, decreasing 40–70% at + 15° across all materials, while material choice modulates stress distribution and fine-tunes structural margin. Polycarbonate and Nylon consistently achieve the highest stiffness > 300 N/m and safety factors > 1.7 at + 5°, HDPE and Polypropylene exhibit intermediate performance, and Polystyrene experiences critical reductions ~ 0.4 at + 15° due to geometric softening. Topologies 2 and 3 provide 8–12% higher stiffness and improved stress distribution relative to 50:50 ribs. The study provides a systematic framework for polymer-based morphing rib design, enabling optimized material selection and structural configuration for lightweight, adaptive aerospace wings.