On the mechanical response of multilayered pentamode lattices equipped with hinged and rigid nodes

Ada Amendola,Gianmario Benzoni,Ida Mascolo

doi:10.1108/prr-07-2018-0022

Ada Amendola, Gianmario Benzoni + Show 1 more

Open Access

https://doi.org/10.1108/prr-07-2018-0022

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Abstract

Purpose This paper aims to review recent literature results on the mechanical response of confined pentamode structures behaving either in the stretching-dominated or the bending-dominated regimes. Design/methodology/approach The analyzed structures consist of multilayer systems formed by pentamode lattices alternated with stiffening plates and are equipped with rigid or hinged connections. Findings It is shown that such structures are able to carry unidirectional compressive loads with sufficiently high stiffness, while showing markedly low stiffness against shear loads. In particular, their shear stiffness may approach zero in the stretching-dominated regime. Originality/value The presented results highlight the high engineering potential of laminated pentamode metamaterials as novel isolation devices to be used for the protection of buildings against shear waves.

Highlights

The peculiar mechanical behavior of confined pentamode lattices, which allows such structures to carry unidirectional compressive loads with sufficiently high stiffness, while showing markedly low stiffness against shear loads, has been illustrated in a series of recent studies available in the literature (Amendola et al, 2016a, 2016b, 2016c, 2017)
Layered pentamode lattices Throughout the manuscript, we examine laminated structures built by stacking layers of pentamode lattices and stiffening plates in the vertical direction
We focus our study on pentamode lattices formed by a single unit cell across the vertical direction and 2 Â 2 unit cells in the horizontal plane

Summary

Introduction

The peculiar mechanical behavior of confined pentamode lattices, which allows such structures to carry unidirectional compressive loads with sufficiently high stiffness, while showing markedly low stiffness against shear loads, has been illustrated in a series of recent studies available in the literature (Amendola et al, 2016a, 2016b, 2016c, 2017). Unidirectional compression loads in the bending-dominated regime because of the confinement effect provided by the stiffening plates Such a feature is essential when developing mechanical metamaterials that need to carry significantly large loads perpendicular to their outer surface while exhibiting low (theoretically zero) rigidity against transverse shear forces (Amendola et al, 2016a, 2016b, 2016c). We first present a collection of numerical results on the response of pentamode metamaterials in the bendingdominated regime induced by the presence of rigid connections between the bars and the plates forming the structure (Amendola et al, 2016a, 2016b, 2016c) In correspondence with such a regime, we observe considerably high ratios between the effective compression and shear rigidities because of the presence of the stiffening plates and to the nonzero bending rigidity of nodes and rods (Amendola et al, 2016a, 2016b, 2016c). We assume that all the members of the examined FCC structures exhibit uniform properties across the thickness

Multilayered pentamode lattices

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