Variable stiffness design optimization of fiber-reinforced composite inlet grilles based on additive manufacturing

This study investigates the integrated design of inlet grid structures through variable stiffness optimization of composite materials. A normal distribution-based fiber optimization interpolation scheme is employed to establish a variable stiffness optimization model that accounts for the continuous variation of fiber layup angles and paths, with the objective of minimizing structural compliance. To overcome manufacturing challenges such as fiber crossover and trajectory jumps, a discrete fiber continuity filtering strategy is introduced, effectively enhancing manufacturability. Using a locally enlarged structure of a representative inlet grid as the engineering background, computational results demonstrate that the proposed strategy significantly improves fiber path continuity and manufacturability, avoiding potential defects in additive manufacturing such as fiber breakage and wrinkling. Short fibers are employed to fabricate composite air intake grille structures, validating the practical applicability of the method. The approach not only satisfies structural load-bearing requirements but also balances electromagnetic stealth performance and lightweight design, providing an effective technical route for the integrated material-design-manufacturing optimization of composite inlet grid structures.