A mechanical metamaterial with real-time tunable bandgap based on pneumatic actuation

Mechanical metamaterials with real-time tunability are an up-and-coming field with great attention. Due to its capability of realizing different mechanical properties, it provides a foundation for the development of intelligent adaptive structures. In this paper, a mechanical metamaterial with real-time tunable bandgap is proposed, exhibiting a wide range of adjustability. With a combination of theory, numerical simulation and experimental studies, the quasi-static mechanical properties and bandgap characteristics of the metamaterial under constant and changeable pressure are investigated, revealing the effect mechanism of cavity pressures on the mechanical properties. The results show that the metamaterial bandgap would move in real time as the cavity pressure changing. Meanwhile, the starting frequency of the bandgap could be varied from 29.6 Hz to 145.83 Hz, with approximately 5 times adjustment. And the bandgap width could be expanded to 5.7 times of the initial state, revealing an excellent wide range of tunable capabilities. Furthermore, the pneumatic actuation is a simple and reliable operation, enabling it to be normally employed in various extreme environments, such as the seabed. The mechanical metamaterials with a wide adjustable bandgap presented in this paper could provide a reference for the field of adaptive structures, offering a promising solution for the design of real-time adjustable mechanical metamaterials.