Energy absorbing properties of open-celled origami-inspired mechanical metamaterials
Jianyu Gao, G.J. McShane
Abstract
Origami-inspired mechanical metamaterials exhibit promising energy absorbing properties due to their unique collapse behaviours and high specific strengths under compression. These are conventionally closed-cell materials, due to their origins in folded-sheet construction. However, within other classes of cellular materials, open-celled architectures have been employed to manipulate and enhance properties, such as specific stiffness, strength and energy absorption. Amongst materials related to origami, cutting sheets has been used to manipulate folding kinematics (i.e. kirigami ). However, within the emerging family of architected materials constructed from three-dimensional arrays of cells derived from origami fold patterns (which display distinctive properties and tunability), there is a lack of understanding of the effect of perforating the facets on the mechanical properties. This is particularly true with regard to the energy absorbing properties, including potential enhancement of the energy absorption per unit weight. Perforated facets could also contribute to the multi-functional design of these materials, e.g. simultaneously affecting the mechanical, thermal and acoustic properties, while maintaining low weight. This paper introduces the design and mechanical properties of open-celled origami-inspired metamaterials. Experimentally validated finite element (FE) analysis is used to evaluate the large strain quasi-static compressive characteristics of these novel metamaterials, with ductile cell wall material properties, across a range of distinct geometric configurations. The numerical results identify configurations that exhibit greater specific energy absorption compared to their closed-celled counterparts. These include: (i) open-celled geometries that collapse predominantly by plastic straining concentrated along fold lines, and (ii) geometries with heterogeneous perforation patterns that stabilise the compressive collapse behaviour.