<p>There has been an explosion in the development of light and strong mechanical metamaterials in the past decade reporting extreme effective properties. These are promising materials for a plethora of applications, from medical textiles to robotic arms and artificial bones. However, their application as structural materials is ultimately limited by their tolerance to damage and defects. While significant advances have been made in reporting extreme properties such as stiffness and strength, material properties that enable us to define the tolerance of metamaterials to defects as yet remain unclear. Via a combination of additive manufactured metamaterial samples with millions of unit cells printed by a large area high resolution additive manufacturing technique, a range of loading conditions and detailed in-situ X-ray tomography all combined with very large-scale numerical simulations we have uncovered the elusive failure mechanics of mechanical metamaterials. The outcome is succinctly summarised in a fracture mechanism-based design map that fully characterises the fracture of three-dimensional metamaterials under arbitrary loading conditions. Our significant findings uncover the fundamental laws of failure in metamaterials. This has led to revising the most basic concepts in the failure of elastic materials and thereby the development of a general design methodology for the emerging class of metamaterials.</p>

A Designer’s Map for Mechanical Metamaterials

Paper Proceedings: https://asmedigitalcollection.asme.org/IDETC-CIE/IDETC-CIE2021/volume/85369

ASME 2021 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference (IDETC/CIE2021)

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