A bio-inspired morphing forebody structure with a continuous and smooth surface for aerospace vehicles

The growing demand for cross-domain intelligent flight in aerospace vehicles has driven the urgent development of multidimensional morphing technologies. Within this context, the morphing forebody has emerged as a critical complement to morphing wings and a key research frontier. However, achieving geometric coordination between morphing mechanisms and aerodynamic surfaces remains a significant challenge, particularly in realizing continuously smooth forebody deformation. Inspired by the spine-muscle synergy of aquatic animals, this paper proposes a bio-inspired rigid-flexible coupled morphing forebody structure (MFS) composed of a morphing forebody mechanism (MFM) and a cellular support structure. The MFS enables synchronized mechanism-support deformation while maintaining a continuous and smooth surface. The kinematic constraints of the MFM are analyzed based on screw theory. Kinematic modeling clarifies the constraint principle governing the shape control points and identifies the mechanism’s achievable morphing envelope. Numerical simulations are conducted to evaluate the mechanism-support synergy and the aerodynamic performance of the morphing forebody. Finally, a prototype is developed for experimental validation. The results demonstrate that the proposed MFS exhibits outstanding morphing capability with preserved surface smoothness. Both strain magnitude and distribution uniformity are improved, while surface error is reduced. This study provides an effective solution to achieve coordinated deformation between internal mechanisms and aerodynamic surfaces in morphing forebody design.