The fracture toughness of demi-regular lattices

Abstract

The properties of lattice materials are strongly influenced by their nodal connectivity; yet, previous studies have focused mainly on topologies with a single vertex configuration. This work investigates the potential of demi-regular lattices, with two vertex configurations, to outperform existing topologies, such as triangular and kagome lattices. We used finite element simulations to predict the fracture toughness of three elastic-brittle demi-regular lattices under mode I, mode II, and mixed-mode loading conditions. The fracture toughness of two demi-regular lattices scales linearly with relative density ̄ρ, and outperform a triangular lattice by 15% under mode I and 30% under mode II. Their mixed-mode fracture envelopes are also up to 43% larger than that of a triangular lattice. The third demi-regular lattice has a fracture toughness that scales with square root of relative density √ ̄ρ and matches the remarkable toughness of a kagome lattice. These findings open new avenues for the development of tougher lightweight materials.