Accordion-like metamaterials with tunable ultra-wide low-frequency band gaps

Abstract

Composite materials with engineered band gaps are promising solutions for wave control and vibration mitigation at various frequency scales. Despite recent advances in the design of phononic crystals and acoustic metamaterials, the generation of wide low-frequency band gaps in practically feasible configurations remains a challenge. Here, we present a class of lightweight metamaterials capable of strongly attenuating low-frequency elastic waves, and investigate this behavior by numerical simulations. For their realization, tensegrity prisms are alternated with solid discs in periodic arrangements that we call 'accordion-like' meta-structures. They are characterized by extremely wide band gaps and uniform wave attenuation at low frequencies that distinguish them from existing designs with limited performance at low-frequencies or excessively large sizes. To achieve these properties, the meta-structures exploit Bragg and local resonance mechanisms together with decoupling of translational and bending modes. This combination allows one to implement selective control of the pass and gap frequencies and to reduce the number of structural modes. We demonstrate that the meta-structural attenuation performance is insensitive to variations of geometric and material properties and can be tuned by varying the level of prestress in the tensegrity units. The developed design concept is an elegant solution that could be of use in impact protection, vibration mitigation, or noise control under strict weight limitations.

A design strategy to match the band gap of periodic and aperiodic metamaterials

“…As a consequence, the local modes excite a very small mass (a portion of the mass of the ligament) and the corresponding eigenfrequency is by far higher than the global one. The mode separation results in activation of extremely wide band gaps, as recently shown for several metamaterial configurations 23 – 26 .…”

Multimaterial printing and characterization for mechanical and surface properties of functionally graded prototype

“…The functional prototypes prepared have significant structural engineering applications 27–32 and the results are in line with the observations made by other investigators. 1–4,23–25,33,34…”

Computational Prediction of the Stability of Tensegrity Structures

“…The large number of infinitesimal mechanisms exhibited by tensegrity theta prisms justify the technical interest toward such structures, which are able to exhibit both soft and stiff modes [16]- [26]. Their use for the design of novel seismic metamaterials [27]- [28] and bandgap structures [29]- [31] is addressed to future work. We also plan to generalize the constitutive response of cables and bars to account for hyperelasticity, nonlinear, nonlocal and unilateral response of the material [32]- [45], through future research.…”