A tensegrity-inspired inertial amplification metastructure with tunable dynamic characteristics

Inertial amplification metastructure, known for its negative effective stiffness, exhibits excellent low-frequency vibration isolation, rendering it widely applicable in mechanical filters and elastic waveguides. However, research into their tunable dynamic characteristics, such as bandgaps, remains scarce. In this paper, we propose an inertial amplification metastructure with tunable dynamic characteristics, leveraging the adjustability of tensegrity. The cell of the metastructure comprises two tensegrity-based units with opposite chirality and an additional resonator, enabling it to selectively transmit axial vibrations. Using theoretical and simulated models, we investigate the static and dynamic characteristics of the metastructure. The results demonstrate that both the magnitude and the sign (positive or negative) of the effective mass and stiffness of the metastructure can be remarkably altered by externally applied forces. Notably, the separation and merging of bandgaps can be achieved with this design. Finally, static and dynamic experiments are conducted to validate our theoretical predictions. The present metastructure holds considerable potential for applications in elastic wave control and wide low-frequency vibration isolation.