Metamaterials have recently attracted significant interest due to their ability to exhibit unconventional properties. By tailoring their internal architecture, metamaterials can be designed to meet specific and innovative functional requirements, enabling advanced control over mechanical or acoustic phenomena. In this work, preliminary results of two distinct applications of metamaterials are presented, focusing respectively on mechanical and acoustic domains. On the mechanical side, the study aims to investigate simple models, such as three-hinged arches, to gain insight into their bistable behavior [1]. Building on this fundamental understanding, the ultimate goal is the development of a metastructure that simultaneously exhibits bistability and peculiar kinematic behavior. On the acoustic side, a two-dimensional metamaterial with high performance in acoustic wave filtering is proposed and analyzed. The acoustic behavior of the system is investigated numerically, considering both periodic configurations [2] and finite structures without periodic boundary conditions, in order to assess the robustness and effectiveness of the filtering mechanism. REFERENCES [1] C. Zhang, X. Yin, R. Chen, K. Ju, Y. Hao, T. Wu, J. Sun, H. Yang and Y. Xu. A review on reprogrammable bistable structures. Smart Mater. Struct., Vol. 33, pp. 093001, 2024. [2] A. Bacigalupo, M.L. De Bellis and D. Misseroni. Design of tunable acoustic metamaterials with periodic piezoelectric microstructure. Extreme Mechanics Letters, Vol. 40, pp. 100977, 2020.