Tailored twist morphing achieved using graded bend–twist metamaterials

This work develops a morphing concept that utilises metamaterial as the passive device for helicopter blades. The metamaterials are created with bend–twist coupling, which enable blade twist under prescribed bending loads. Finite element analysis (FEA) is performed to investigate influence of unit cell configurations on coupling properties metamaterials. numerical models then validated experimentally through set tests conducted additively manufactured prototypes. Finally, model used design graded metamaterial, where aspect ratio gradually changes along span, providing unique and allowing tailored be obtained. results suggest capable introducing optimised nonlinear twists during different flight conditions including both hover forward flight.