Using heterogeneous fold patterns to manipulate the compressive collapse mechanisms of ductile origami-inspired metamaterials

Origami-inspired mechanical metamaterials are recognised for their exceptional property tuneability and controllable collapse behaviour. Their design often originates from origami folding kinematics, with an array of facets deforming along hinge lines, preserving flat foldability. This study introduces a new heterogeneous origami-inspired architecture that allows the kinematics to be selectively disrupted. The concept allows flat foldable and non-flat foldable cells to be combined in almost arbitrary patterns, in turn manipulating the collapse mechanisms, and mechanical properties. The potential of this concept is shown in the context of compressive collapse of ductile metamaterials, using a combination of finite element simulations and experiments, using additively manufactured 316 L stainless steel specimens. The results reveal that, by employing this heterogeneous architecture, properties such as compressive strength and energy absorption are enhanced by the interactions between contrasting cell types. This strategy expands the rich design space, offering new opportunities for properties by design.