Unprecedented mechanical wave energy absorption observed in multifunctional bioinspired architected metamaterials

This paper presents bioinspired architected metamaterials designed to absorb both sound and stress wave energy. Inspired by cuttlebone, these metamaterials use a weakly-coupled design with heterogeneous multilayered resonators for acoustic absorption and asymmetric cambered cell walls for mechanical response. Experimental results show an average absorption coefficient of 0.80 from 1.0 to 6.0 kHz, with 77% of data points exceeding 0.75, using a compact 21 mm thickness. A high-fidelity model reveals air friction damping and broadband behavior due to multimodal hybrid resonance. The cambered cell walls enable progressive deformation, leading to ultrahigh specific energy absorption (50.7 J/g), a 558.4% increase over a straight-wall design. The study proposes a framework for acousto-mechanical metamaterials.

Zhendong Li, Xinxin Wang, Kexin Zeng, Zichao Guo, Chong Li, Xiang Yu, Seeram Ramakrishna, Zhonggang Wang, Yang Lu