Nonlinear chaotic dynamics of functionally graded graphene composite curved plates for the wings of low-altitude aircrafts

Low-altitude aircrafts are subject to complex aerodynamic and environmental disturbances, which place stringent demands on lightweight structures with reliable dynamic stability. Functionally graded graphene-reinforced composites (FG-GRCs), owing to their high specific strength and tunable properties, are promising candidates for load-bearing and vibration-sensitive components in such vehicles. This study investigates the complex nonlinear dynamics, particularly multi-pulse chaotic vibrations, of cantilever laminated curved plate subjected simultaneous transverse and in-plane parametric excitations. A nonlinear dynamic model incorporating geometric curvature and material gradation effects is established and validated by finite element analysis, revealing a critical 1:1 internal resonance between specific modes under particular geometric configurations. The extended Melnikov method is applied to theoretically predict the Shilnikov-type multi-pulse chaotic motions. Bi-parameter threshold surfaces derived from the Melnikov function are proposed and quantitatively validated against two-dimensional maximum Lyapunov exponent (MLE) diagrams, exhibiting good agreement in identifying chaotic regions. Extensive numerical simulations, including bifurcation diagrams, phase portraits, Poincaré maps, and time histories, confirm the presence of complex dynamics such as periodic motions, chaotic vibrations, and their transitions. The results provide crucial insights into the parameter domains that may trigger hazardous chaotic responses in FG-GRC curved plates, supporting the safe and reliable design of next-generation low-altitude aircraft structures such as wings, rotor arms, and fuselage skins.