Multifunctional TPMS-based metastructures

Abstract

Addressing the dual demands of concurrent low-frequency noise suppression and superior mechanical performance in lightweight structures remains a critical engineering challenge. This study proposes an innovative design and optimization strategy for novel multifunctional TPMS-based metastructures, enabling synergistic enhancement of both acoustic and mechanical functionalities. Two types of multifunctional TPMS-based metastructures, designated as Types A and B, are constructed with thickened triple periodic minimal surfaces (TPMS), micro-perforated panels (MPP), and solid panels (SP). The acoustics and mechanical performance of the proposed metastructures are quantified by the sound absorption coefficient and the equivalent bending stiffness, respectively. Subsequently, an optimization framework integrating a non-dominated sorting genetic algorithm II (NSGA-II) is developed to optimize low-frequency sound absorption bandwidth and equivalent bending stiffness. With the optimized configuration, Type A achieves effective sound absorption at 343–579 Hz (absorption coefficient α > 0.8) and an equivalent bending stiffness of 5.96. Additionally, we reveal the sound absorption mechanism by normalized acoustic resistance and normalized acoustic reactance as well as vibration velocity and acoustic energy dissipation density of the air particles inside the micro-perforations. A sound absorption theoretical model for the multifunctional TPMS-based metastructures is developed via the electro-acoustic analogy method and verified by finite element and experimental approaches. The equivalent bending stiffness is obtained through finite element and experimental. In addition, we have investigated the effect of geometrical parameters on the sound absorption coefficient and the equivalent bending stiffness. This study offers a novel approach to the multifunctional design of lightweight structures.