Models for the elastic deformation of honeycombs
TL;DR: In this paper, a theoretical model was developed for predicting the elastic constants of honeycombs based on the deformation of the honeycomb cells by flexure, stretching and hinging, which can be used to derive expressions for the tensile moduli, shear moduli and Poisson's ratios.
About: This article is published in Composite Structures.The article was published on 1996-08-01. It has received 804 citations till now. The article focuses on the topics: Deformation (engineering) & Honeycomb structure.
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TL;DR: Wood nanofibrils are used to prepare porous cellulose nanopaper of remarkably high toughness and the large strain-to-failure means that mechanisms, such as interfibril slippage, also contributes to inelastic deformation in addition to deformation of the nan ofibrils themselves.
1,187 citations
TL;DR: In this paper, the relationship among structures, materials, properties and applications of auxetic metamaterials and structures is discussed. And the challenges and future work on the topic of auxetics are also presented to inspire prospective research work.
Abstract: Materials and structures with negative Poisson's ratio exhibit a counter-intuitive behaviour. Under uniaxial compression (tension), these materials and structures contract (expand) transversely. The materials and structures that possess this feature are also termed as 'auxetics'. Many desirable properties resulting from this uncommon behaviour are reported. These superior properties offer auxetics broad potential applications in the fields of smart filters, sensors, medical devices and protective equipment. However, there are still challenging problems which impede a wider application of auxetic materials. This review paper mainly focuses on the relationships among structures, materials, properties and applications of auxetic metamaterials and structures. The previous works of auxetics are extensively reviewed, including different auxetic cellular models, naturally observed auxetic behaviour, different desirable properties of auxetics, and potential applications. In particular, metallic auxetic materials and a methodology for generating 3D metallic auxetic materials are reviewed in details. Although most of the literature mentions that auxetic materials possess superior properties, very few types of auxetic materials have been fabricated and implemented for practical applications. Here, the challenges and future work on the topic of auxetics are also presented to inspire prospective research work. This review article covers the most recent progress of auxetic metamaterials and auxetic structures. More importantly, several drawbacks of auxetics are also presented to caution researchers in the future study.
603 citations
TL;DR: In this article, a clear classification of mechanical metamaterials have been established based on the fundamental material mechanics, which can be divided into strong-lightweight (E/ρ), pattern transformation with tunable stiffness, negative compressibility (−4G/3), and strong light-weight (S/ρ).
554 citations
Cites background from "Models for the elastic deformation ..."
...These auxetic metamaterials include re-entrant or hinged honeycombs and foams [28,30,76,339,347], similar to another directional semi-auxetic solid based on combining or rotating units....
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...26), similar to the folded-in cells fabricated from polyurethane foam, including various re-entrant open-cell microstructures [76,339,347], rotating squares [138,337,341,348] or triangles [288,289,291,344]; (ii) NPR induced by an elastic instability, particularly the missing rib models [339,349] to pattern transformation [26,226,308] (Section 5....
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TL;DR: In this paper, the authors summarized research work related to materials with zero, or negative Poisson's ratio, referred to as auxetic materials, and predicted that future research will be in the direction of disordered microstructures utilizing the homogenization method.
483 citations
TL;DR: The models presented provide not only quantitative information about the mechanical properties of SLGS, but also insight into the equivalent mechanical deformation mechanisms when the SLGS undergoes small strain uniaxial and pure shear loading.
Abstract: The elastic moduli of single layer graphene sheet (SLGS) have been a subject of intensive research in recent years. Calculations of these effective properties range from molecular dynamic simulations to use of structural mechanical models. On the basis of mathematical models and calculation methods, several different results have been obtained and these are available in the literature. Existing mechanical models employ Euler-Bernoulli beams rigidly jointed to the lattice atoms. In this paper we propose truss-type analytical models and an approach based on cellular material mechanics theory to describe the in-plane linear elastic properties of the single layer graphene sheets. In the cellular material model, the C-C bonds are represented by equivalent mechanical beams having full stretching, hinging, bending and deep shear beam deformation mechanisms. Closed form expressions for Young's modulus, the shear modulus and Poisson's ratio for the graphene sheets are derived in terms of the equivalent mechanical C-C bond properties. The models presented provide not only quantitative information about the mechanical properties of SLGS, but also insight into the equivalent mechanical deformation mechanisms when the SLGS undergoes small strain uniaxial and pure shear loading. The analytical and numerical results from finite element simulations show good agreement with existing numerical values in the open literature. A peculiar marked auxetic behaviour for the C-C bonds is identified for single graphene sheets under pure shear loading.
481 citations
References
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01 Aug 1988TL;DR: The linear elasticity of anisotropic cellular solids is studied in this article. But the authors focus on the design of sandwich panels with foam cores and do not consider the properties of the materials.
Abstract: 1. Introduction 2. The structure of cellular solids 3. Material properties 4. The mechanics of honeycombs 5. The mechanics of foams: basic results 6. The mechanics of foams refinements 7. Thermal, electrical and acoustic properties of foams 8. Energy absorption in cellular materials 9. The design of sandwich panels with foam cores 10. Wood 11. Cancellous bone 12. Cork 13. Sources, suppliers and property data Appendix: the linear-elasticity of anisotropic cellular solids.
8,946 citations
Book•
01 Jan 1965TL;DR: In this article, the authors propose formulas for stress and strain in the form of formulas for strain and stress, which are derived from the formula for stress-and-stress and strain.
Abstract: Formulas for stress and strain , Formulas for stress and strain , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
1,830 citations
TL;DR: In this paper, the mechanical properties of two-dimensional cellular materials, or honeycombs, are analyzed and compared with experiments, in terms of bending, elastic buckling and plastic collapse of the beams that make up the cell walls.
Abstract: The mechanical properties (linear and nonlinear elastic and plastic) of two-dimensional cellular materials, or honeycombs, are analysed and compared with experiments. The properties are well described in terms of the bending, elastic buckling and plastic collapse of the beams that make up the cell walls.
1,567 citations
943 citations