3D‐Printed Mechanical Metamaterials with High Energy Absorption

Abstract

Metamaterials [1,[2][3][4] are rational artificial materials with unique structural designs to manipulate and control light, [5] sound, [6,7] mechanical stress, [8,9] etc., leading to previously inacces sible properties in photonic, [10] acoustic, [6] mechanical, [11,12] and many other physical aspects. 3D auxetic materials with highly ordered packing are first observed in the deformation of metallic crystal. [13] To date, the 3D metamaterials facilitate the combinations of mechanical properties that are in prin ciple antagonistic, such as ultrahigh stiffness, high damping capability, or negative Poisson's ratio. [14][15][16] These properties are derived both from the geometrical arrangement of those

Reversible energy absorbing meta-sandwiches by FDM 4D printing

“…Geometrical parameters of meta-structures play crucial role on the structural performance. Several comprehensive research works [23,[34][35][36][37][38][39] were conducted on investigating the effects of geometrical parameters on auxeticity (negative Poisson's ratio) and energy absorption of meta-structures. Yang et al [37] observed that the negative Poisson's ratio increases with increasing re-entrant angle and decreasing horizontal to oblique length ratio.…”

“…Regarding the struts thickness, Wang et al [39] showed that with increase in strut thickness of the re-entrant structure, the auxeticity decreases gradually and finally reaches a plateau while the compression Young's modulus and relative density increase monotonically. It was also proved that the higher the relative density, the larger the energy absorption capacity [34][35]. Hence, increase in strut thickness of the re-entrant auxetic structure results in increase in relative density and therefore increase in energy absorption capacity.…”

3D Printing of Polymeric Multi-Layer Micro-Perforated Panels for Tunable Wideband Sound Absorption

“…Polymers 2020, 12, x FOR PEER REVIEW 3 of 17 rapid manufacturing of prototypes [40]. It has great potential to expand for mass manufacturing in acoustic areas.…”

“…The main target frequency range in this study is set as 800-1200 Hz since most of the frequencies of the traffic noises are within this range [40]. The sound absorption at other frequencies can also be reached at the same time as multiple peaks with large absorption coefficients achieved using the multi-layer MPPs.…”

“…This support-free feature is ideal for fabricating complex hollow structures with multiple layers where conventional methods would require post-fabrication assembly to integrate individual components into multiple layers. The utilization of 3D printing techniques can facilitate the proof of concept of the designed acoustic structures by rapid manufacturing of prototypes [40]. It has great potential to expand for mass manufacturing in acoustic areas.…”