Optimization design of lightweight multi-functional non-local metastructure for broadband sound absorption and electromagnetic dissipation

In recent decades, noise pollution and electromagnetic radiation have emerged as the two primary sources of global public hazard. In order to offset the detrimental impact of these pollutants on industrial output and human wellbeing, a metastructure that is capable of simultaneously fulfilling the functions of electromagnetic dissipation and noise absorption is proposed. The non-local lightweight multifunctional metastructure (MFMS), designed through an integrated material-structure-functionality approach, simultaneously enables broadband sound absorption and electromagnetic dissipation. The MFMS achieves an acoustic absorption of approximately 0.8 within the frequency range of 500 Hz to 1,000 Hz. Moreover, the MFMS displays an electromagnetic reflectivity below -10 dB across the majority of the frequency range of 2–40 GHz. The experiment and simulation reveal that the broadband sound absorption mechanism is based on the structural impedance match and parallel operation of multiple resonance modes. In contrast, the mechanism of electromagnetic dissipation is a consequence of the combined influence of structural impedance matching and dielectric loss principles. Overall, an innovative multi-objective optimization method is proposed to design the MFMS.