Stiffening multistable origami-inspired deployable structures from embeddable bistable units

In this work, we present a method for stiffening lightweight Origami-inspired single-degree of freedom (DOF) (e.g. Miura-Ori) and multiple DOF Origami surfaces from incompatibilities imposed by embedding bistable units. The stiffening of these reconfigurable structures is achieved by strategically introducing the bistable units in the creases to lock their DOFs. We compare two methods for attaining stiffening from bistability: the Dual Offset Hinge (DOH) unit and the Binder Clip Inspired (BCI) unit. Both unit designs are experimentally characterised, and their stiffnesses are modelled as a function of deformation with fitted equations. We show that the locking ability of the embedded units helps maintain the stiffness of the Origami-inspired structures under distributed loads, with or without coupling the initial and final hinge twist angles. Applications include stiffening aircraft wings, foldable sails for multimodal vehicles, and space applications such as supporting solar panel arrays on orbital and extraterrestrial vehicles. • We present a method for stiffening single- and multi-degree-of-freedom Origami via strain incompatibility from bistable units. • We stiffen the surfaces by embedding bistable units in the creases to lock their Degrees of Freedom and control their shape. • We model and experimentally study the stiffening of two units: the Dual Offset Hinge unit and the Binder Clip Inspired unit. • We show that the locking effect from the bistable units effectively maintains the deployed shape and substantially stiffens the origami structures under loading. • The stiff units transfer structural capacity to the Origami, providing a basis for design by maximising local stiffness.