Geometric assembly of rigid-foldable morphing sandwich structures

•An alternative to the existing morphing sandwich mechanism is proposed.•Alternative mechanism located unconnected face hinges at core ridge locations.•A mechanism family was developed with Miura-derivative core geometries.•Fan-shaped plate, cylindrical shell, and conical shell mechanisms are created.

Morphing plate-based sandwich mechanisms consist of three layers: an inner core designed to achieve a particular deployed geometric envelope and two outer faces designed to preserve core rigid-foldability from flat-folded to a deployed sandwich form. This paper examines rigid-foldable morphing sandwich mechanisms based on the Miura rigid origami pattern. An alternative mechanism is developed that has improved stability and locking capability compared with the existing mechanism reported previously. These improvements are demonstrated with steel prototypes. The alternative mechanism is then extended to form a family of new morphing sandwich structures, including a fan-shaped mechanism, and single-curved cylindrical and conical mechanisms. Each are derived by substituting the base Miura core pattern with a Miura-derivative pattern, and attaching faces that have compatible rigid-foldability and avoid self-intersection during deployment. Morphing mechanisms and geometric derivations are validated with physical prototypes.

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