Gyro-elastic beams for the vibration reduction of long flexural systems

Carta, G.; Jones, I. S.; Movchan, N. V.; Movchan, A. B.

doi:10.1098/rspa.2017.0136

Cited by 31 publications

(28 citation statements)

References 38 publications

(54 reference statements)

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“…In parallel, new possibilities to dissipate the seismic energy in the superstructures themselves are emerging thanks to the contributions of auxetic materials [57] and metamaterials [52].…”

Section: Discussionmentioning

confidence: 99%

“…By another way but with the aim of reducing the effect of the waves on the structure, recent research on gyrobeams implemented in the structure itself [52] open a new perspective in chiral metamaterial design and in a wide range of applications in earthquake wave filtering. It has been demonstrated that the role of gyrobeams is primarily to create low-frequency 'energy sinks', in which waves generated by external excitations are channelled.…”

Section: New Dissipative Structuresmentioning

confidence: 99%

See 1 more Smart Citation

Emergence of seismic metamaterials: Current state and future perspectives

2020

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Following the advent of electromagnetic metamaterials at the turn of the century, researchers working in other areas of wave physics have translated concepts of electromagnetic metamaterials to acoustics, elastodynamics, as well as to heat, mass and light diffusion processes. In elastodynamics, seismic metamaterials have emerged in the last decade for soft soils structured at the meter scale, and have been tested thanks to full-scale experiments on holey soils five years ago. Born in the soil, seismic metamaterials grow simultaneously on the field of tuned-resonators buried in the soil, around building's foundations or near the soil-structure's interface, and on the field of above-surface resonators. In this perspective article, we quickly recall some research advances made in all these types of seismic metamaterials and we further dress an inventory of which material parameters can be achieved and which cannot, notably from the effective medium theory perspective. We finally envision perspectives on future developments of large scale auxetic metamaterials for building's foundations, forests of trees for seismic protection and metamaterial-like transformed urbanism at the city scale.

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“…In parallel, new possibilities to dissipate the seismic energy in the superstructures themselves are emerging thanks to the contributions of auxetic materials [57] and metamaterials [52].…”

Section: Discussionmentioning

confidence: 99%

Section: New Dissipative Structuresmentioning

confidence: 99%

Emergence of seismic metamaterials: Current state and future perspectives

2020

View full text Add to dashboard Cite

show abstract

“…Due to the simplicity of expression (45) for the longitudinal field, the twelve boundary conditions (15), (16), and (17) reduce to four continuity conditions at the interfaces between the two substructures, which considering the quasi-periodicity condition (37), are equivalent to the following homogeneous linear system for the four amplitudes U…”

Section: Purely Axial Vibrations: System (0)mentioning

confidence: 99%

Nested Bloch waves in elastic structures with configurational forces

Corso

Tallarico

Movchan

et al. 2019

Phil. Trans. R. Soc. A.

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Small axial and flexural oscillations are analyzed for a periodic and infinite structure, constrained by sliding sleeves and composed of elastic beams. A nested Bloch-Floquet technique is introduced to treat the non-linear coupling between longitudinal and transverse displacements induced by the configurational forces generated at the sliding sleeve ends. The action of configurational forces is shown to play an important role from two perspectives. First, the band gap structure for purely longitudinal vibration is broken so that axial propagation may occur at frequencies that are forbidden in the absence of a transverse oscillation and, second, a flexural oscillation may induce axial resonance, a situation in which the longitudinal vibrations tend to become unbounded. The presented results disclose the possibility of exploiting configurational forces in the design of mechanical devices towards longitudinal actuation from flexural vibrations of small amplitude at given frequency.

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“…To improve the acoustic performances of the blocky system and to achieve ultra-low frequency stop bands, the blocks have been coupled with an elastic half-space model as a Winkler support. In this case, the low frequency branch has a non-vanishing frequency at the long wave-length limit and the opening of a ultra-low frequency band gap may be obtained (see Gei et al, 2009, Brun et al, 2012, Piccolroaz and Movchan, 2014, and Carta et al, 2017. Moreover, a convenient fine approximation of the dispersion functions of the Lagrangian model is pursued through the formulation of an equivalent continuum model.…”

Section: Introductionmentioning

confidence: 99%

Acoustic waveguide filters made up of rigid stacked materials with elastic joints

et al. 2019

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The acoustic dispersion properties of monodimensional waveguide filters can be assessed by means of the simple prototypical mechanical system made of an infinite stack of periodic massive blocks, connected to each other by elastic joints. The linear undamped dynamics of the periodic cell is governed by a two degree-of-freedom Lagrangian model. The eigenproblem governing the free propagation of shear and moment waves is solved analytically and the two dispersion relations are obtained in a suited closed form fashion.Therefore, the pass and stop bandwidths are conveniently determined in the minimal space of the independent mechanical parameters. Stop bands in the ultra-low frequency range are achieved by coupling the stacked material with an elastic half-space modelled as a Winkler support. A convenient fine approximation of the dispersion relations is pursued by formulating homogenised micropolar continuum models. An enhanced continualization approach, employing a proper Maclaurin approximation of pseudo-differential operators, is adopted to successfully approximate the acoustic and optical branches of the dispersion spectrum of the Lagrangian models, both in the absence and in the presence of the elastic support.

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Gyro-elastic beams for the vibration reduction of long flexural systems

Cited by 31 publications

References 38 publications

Emergence of seismic metamaterials: Current state and future perspectives

Emergence of seismic metamaterials: Current state and future perspectives

Nested Bloch waves in elastic structures with configurational forces

Acoustic waveguide filters made up of rigid stacked materials with elastic joints

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