Meta-structures for energy absorption: materials, designs, and applications in additive manufacturing and its future scope

The rational design of artificial materials with dynamic performance abilities is necessary due to their applications in different fields. Meta-structures are being explored intensively because of their unusual qualities from natural materials, and these traits include Negative Poisson's ratio, high stiffness, high energy absorption, and negative thermal expansion. Meta-structures can be fabricated using additive manufacturing (AM) and obtained from macro- to meso scale; hence are scale-independent. AM fabricates designed geometry using materials like metals, metal alloys, composites, shape memory alloys, and elastomers. AM is a versatile process that can manufacture meta-structures with different geometries, including chiral, re-entrant, cellular, etc. This work comprehensively reviews the materials necessary to manufacture meta-structures, their alternative geometries, and the impact of configuration changes on their mechanical properties. Subsequently, the applications in many disciplines, such as vibration mitigation, noise cancellation, and electromagnetic shielding, as well as their limits and future potential, are also examined.