Impact dynamics of mechanical metamaterials: A short review and perspective

Mechanical metamaterials, with their unique properties, have been increasingly investigated as lightweight, high‑strength impact‑resistant solutions for aerospace, military, transportation, and biomedical applications. In this paper, recent advanced studies in mechanical metamaterials under impact loads are briefly reviewed. On the basis of structural form, four primary types of metamaterials are categorized: mass-spring system, rod/beam-based, plate/shell-based and other specialized types of metamaterials. Additionally, their intended energy-absorption mechanisms and loading-rate‑dependent mechanical responses are discussed. Finally, potential future research directions are proposed, including studies of strain rate and inertial effects, stress wave propagation, localized impact, size effect and multi-scale effect, multifunctional design and AI-assisted on-demand design. This paper highlights key strategies and areas for innovation in the development of next-generation impact-resistant mechanical metamaterials.