Defect-driven process design for warm variable-curvature roll bending of aerospace aluminum extrusions: from necking to buckling suppression

초록

Flexible roll bending offers a die-flexible alternative to stretch bending for variable-curvature aerospace aluminum extrusions. This study presents a defect-driven design framework integrating temperature-dependent anisotropic modeling (Voce–Hill 1948), M–K-based necking assessment, and evolutionary FE process design. A fixed-end single-roller configuration caused severe strain localization, whereas continuous three-roll bending reduced the necking risk but produced flange buckling with a maximum out-of-plane displacement of approximately 8 mm. By introducing two vertical load rollers and lateral guide rollers, the final multi-axis configuration stabilized the L-shaped AA7075-O profile under warm-forming conditions. In contrast, the T-shaped AA2024-O profile remained buckling-prone within the explored external-roller constraint scheme, revealing a geometry-dependent process boundary. Physical trials using a custom-built prototype successfully formed the L-shaped profile, and 3D optical scanning showed relative errors of 4.4% in chord length and 10.3% in camber depth compared with FE predictions. © The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature 2026.

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