Reconfigurable origami-based metamaterials with a transition between compact flat-foldable and load-bearing states

• Origami metamaterial switching between flat-foldable and load-bearing states. • Demonstrates high load-bearing capacity with kinematically singular state. • Quantifies the influence of geometric parameters on load-carrying performance. Graphical abstract Origami-based metamaterials offer significant potential for lightweight, compact, and geometrically programmable deployable structures. However, most existing designs face a fundamental trade-off between flat-foldability and load-bearing capacity, limiting their practical engineering applications. This study proposes a reconfigurable origami metamaterial that enables in-situ switching between a compact flat-folded state and a mechanically stable, load-bearing configuration without inducing facet deformation or modifying the crease pattern. The transition is achieved through complementary out-of-plane and parallel self-locking mechanisms based on hard-stop interactions, which drive the structure into a kinematically singular state within a rigid-origami framework. Owing to their foundation in a six-crease vertex and four-bar kinematics, the proposed mechanisms are independent and inherently scalable, allowing adaptation to a wide range of flat-foldable geometries. The concept is realised in a volumetric cuboidal unit composed of waterbomb-derived facets, termed the waterbomb-cuboid origami (WC-ori), which deploys through a single degree of freedom with simultaneous actuation. The geometric and kinematic principles governing the state transition are first established through kinematic analysis and mechanical bifurcation considerations. Experimental axial compression tests and finite-element simulations are then conducted on WC-ori prototypes fabricated from cardboard to validate the proposed load-bearing mechanism. Results demonstrate that switching from the flat-folded to the self-locked deployed configuration enhances the load-carrying capacity by approximately two orders of magnitude relative to the unit self-weight. A parametric numerical study further elucidates the influence of hard-stop geometry and folding angles on load-bearing performance and volumetric efficiency, highlighting the potential of WC-ori units for scalable tessellated structural systems.