Tunable wave propagation by varying prestrain in tensegrity-based periodic media

TL;DR

This study explores how varying prestrain in tensegrity-based periodic structures can significantly alter their wave propagation characteristics, revealing phase transitions, unique dispersion properties, and potential for tunable dynamic responses.

Contribution

It demonstrates that prestrain levels can control wave velocities and phase states in tensegrity structures, introducing a new method for tunable wave manipulation in these materials.

Findings

Wave velocities jump at critical prestrain values, indicating phase transitions.

Low wave velocities occur at zero effective stiffness in low prestrain regimes.

Shear waves can travel faster than longitudinal waves in certain prestrain conditions.

Abstract

This paper investigates the dynamic properties of one, two and three-dimensional tensegrity-based periodic structures introduced in Rimoli and Pal, Comp. B, 2017, which are here termed as tensegrity beams, plates and solids, respectively. We study their linear wave propagation properties and show that in each case, these properties can be significantly altered by the prestrain in the cables. As the prestrain is varied, we observe jumps in the wave velocities at two critical prestrain values, which define transitions between the three distinct phases of these structural assemblies. At low cable prestrains, the wave speeds are zero as the lattices have zero effective stiffness. At moderate prestrains, the wave speed is nonzero and finally, at prestrain levels where the bars buckle, the wave speed decreases to a lower value. Dispersion analysis on these beams, plates and solids reveal unique properties such as very low wave velocities compared to their constituent material and the existence of flat bands at low frequencies. Furthermore, we find that shear waves travel faster than longitudinal waves in tensegrity solids in a range of cable prestrains. Finally, we verify the key observations through detailed numerical simulations on finite tensegrity solids.