Laser additive manufacturing of hierarchical multifunctional chiral metamaterial with distinguished damage-resistance and low-frequency broadband sound-absorption capabilities.

[Display omitted] • A hierarchical multifunctional chiral metamaterial (HMCM) is proposed for both excellent energy dissipation and low-frequency broadband sound absorption. • The distance ratio and wall thickness distribution of HMCM have vital effects on energy absorption performance. • The quasi-perfect absorption of the HMCM is attributed to the coherent coupling effect and hierarchical scale effect. • The multifunctional performance of the HMCM was investigated systematically through experimental, numerical, and theoretical methods. Traditional materials or advanced artificially engineered metamaterials are incapable of effectively addressing the simultaneous challenges of impact energy hazards and low-frequency noise. There is an urgent need for multifunctional materials that can address this multi-physics field coupling problem. Herein, a hierarchical multifunctional chiral metamaterial (HMCM) is proposed for damage-resistance and low-frequency broadband sound-absorption capabilities fabricated by means of laser powder bed fusion technology. Cavity resonators with internally extended tubes with hierarchical chiral configuration were selected as primary units. The damage-resistance performance of the HMCM was investigated systematically through experimental, numerical, and theoretical methods. Crashworthiness design and optimization on the multifunctional chiral metamaterial were implemented to explore the effect of geometrical parameters including distance ratio and wall thickness distribution on crushing resistance. It was determined that specific configurations in these parameters significantly enhance mechanism for dissipating energy of the HMCM. Furthermore, the designed metamaterial has been experimentally, numerically, and theoretically proven to possess quasi-perfect broadband sound absorption in the target range of 425 Hz to 553 Hz with an average sound absorption coefficient exceeding 0.9. Overall, this work not only offers a promising solution for designing multifunctional metamaterials but also highlights the potential of additive manufacturing techniques in the development of such sophisticated materials. [ABSTRACT FROM AUTHOR]