Metallic Mechanical Metamaterials Produced by LPBF for Energy Absorption Systems

Metallic mechanical metamaterials have attracted the attention of many industrial sectors due to their unique properties which enable them to outperform natural materials in unconventional ways. Metal metamaterials encompass multiple fields, including materials science, mechanics, and industrial technology, and they have become particularly popular following the implementation of reliable, high-resolution, efficient metal additive manufacturing processes. This review takes a joint approach, providing an in-depth analysis of the base materials and geometries that characterize metamaterials in order to understand their behavior in response to impacts at different load regimes and to offer readers a critical overview of the most suitable design choices for energy absorption systems. Furthermore, this review highlights advanced metamaterial optimization methods that are useful for increasing the mechanical energy absorbed avoiding peak impulse transfer to the people, instrumentation, or generic loads that mechanical metamaterials are designed to protect.