Crack path-engineered 2D octet-truss lattice with bio-inspired crack deflection

Abstract

Abstract Engineered lattice materials with pre-designed crack paths can provide critical component protection and tunable fracture energy. However, most existing crack path design methods require a change in the local topology of the material, which induces inconsistency in the material density and additional topological design complexity. In this study, the authors propose an optical programing method via digital light processing (DLP) to engineer the crack path in lattice materials without altering the material’s topological design. In this method, the effect of curing light intensity on the mechanical properties of the material is studied to develop an effective crack path engineering method, followed by the generation of a bio-inspired crack path deflection on an octet-truss lattice structure. Based on a derived theoretical model of material properties, a crack path engineering method is proposed by applying a grayscale on the desired crack path locations in DLP printing layer images. To mimic the weak crack deflection interfaces of natural materials, vertical crack deflection zones are designed with different relative positions on the octet-truss lattice structures. Consequently, a 15%–152% increase in quantitively controllable fracture energy is observed.