Multi‐Level Bioinspired Microlattice with Broadband Sound‐Absorption Capabilities and Deformation‐Tolerant Compressive Response

Abstract

Owing to the omnipresent noise and crash hazards, multifunctional sound‐absorbing, and deformation‐tolerant materials are highly sought‐after for practical engineering design. However, challenges lie with designing such a material. Herein, leveraging the inherent mechanical robustness of the biological cuttlebone, by introducing dissipative pores, a high‐strength microlattice is presented which is also sound‐absorbing. Its absorption bandwidth and deformation tolerance are further enhanced by introducing another level of bioinspiration, based on geometrical heterogeneities amongst the building cells. A high‐fidelity microstructure‐based model is developed to predict and optimize properties. Across a broad range of frequencies from 1000 to 6300 Hz, at a low thickness of 21 mm, the optimized microlattice displays a high experimentally measured average absorption coefficient of 0.735 with 68% of the points higher than 0.7. The absorption mechanism attributes to the resonating air frictional loss whilst its broadband characteristics attribute to the multiple resonance modes working in tandem. The heterogeneous architecture also enables the microlattice to deform with a deformation‐tolerant plateau behavior not observed in its uniform counterpart, which thereby leads to a 30% improvement in the specific energy absorption. Overall, this work presents an effective approach to the design of sound and energy‐absorbing materials by modifying state‐of‐the‐art bioinspired structures.

Harnessing cavity dissipation for enhanced sound absorption in Helmholtz resonance metamaterials

“…It is worth noting that common absorbers usually display comparable or poor average coefficients, within a larger thickness of 20 to 30 mm. For instance, examples include a layer-by-layer lattice, 15 hollow truss, 22 bioinspired structure, 26 window-foams, 38 graded phononic crystals, 39 etc. Performance would be unfavourable if the HHA is considered instead.…”

“…These include dense truss lattices, 14,22 plate lattices with pores, 14,[23][24][25] and layer-by-layered perforated plate lattices. 15,26,27 As can be seen, Helmholtz resonance is regarded as one of the most effective and widely adopted mechanisms for sound absorption.…”

Deep Learning in Mechanical Metamaterials: From Prediction and Generation to Inverse Design

“…However, designing such complex building blocks is largely dependent on experienced designers and requires extensive trial-and-error efforts. Once an idea is conceived, a building block can be modeled using computer-aided design (CAD) modeling tools, taking inspiration from crystalline solids, [16][17][18]26,27] creatures, [28][29][30] nature, [31][32][33][34] and arts and crafts. [24,25,35,36] Alternatively, computational algorithms can be used to generate building blocks within bounding boxes, using techniques such as topology optimization, [37][38][39][40][41][42] phase-field modeling, [43][44][45][46] and Voronoi tessellation.…”

Breaking the Tradeoffs between Different Mechanical Properties in Bioinspired Hierarchical Lattice Metamaterials

“…The recent advancements in additive manufacturing technology have paved new avenues for achieving extraordinary mechanical properties in advanced metamaterials by architecting novel cell configurations. [11][12][13][14] Over the last decade, a substantial body of research has been dedicated to exploring the design, fabrication, and microstructural characterization of lattice metamaterials for further enhancement of mechanical properties. Researchers have proposed novel designs, including hierarchical architectures, [15,16] dualphase hybrid hardening, [17,18] and topology gradient, [19,20] aimed at improving the mechanical performance of these metamaterials.…”