Designing strong and tough lattice materials: the advantage of nonlocal lattices

Developing lightweight lattice materials that possess exceptional strength, stiffness, and toughness (or energy absorption) simultaneously remains a significant challenge. In this study, we develop a novel design strategy: incorporating nonlocal interactions into lattice beams, creating “nonlocal lattices”. Utilizing simulation experiments, we investigated the bending behaviors of these lattices, with a particular focus on their damage evolution. Interestingly, these nonlocal lattices, categorized as stretch-dominated, exhibit extraordinary peak force (strength) and stiffness (modulus) comparable to traditional stretch-dominated lattices, while maintaining superior energy absorption (toughness). Analysis of damage evolution within the lattice beams reveals a transition from localized to dispersed damage patterns. This transition delays strain localization, thereby improving material utilization efficiency. Furthermore, stronger nonlocal interaction leads to a more dispersed damage zone, further improving materials utilization efficiency. These findings demonstrate that nonlocal lattices achieve excellent energy dissipation (toughness) without compromising strength and stiffness. This highlights the crucial role of nonlocal interactions in governing strain localization within lattice materials. The design strategy here unlocks new inspirations for the development of strong and tough lightweight materials.