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Journal ArticleDOI

A Gradient Cellular Core for Aeroengine Fan Blades Based on Auxetic Configurations

TL;DR: In this paper, gradient cellular centresymmetric auxetic configurations are evaluated as potential cores for aeroengine fan blades, and optimized to reduce the dynamic response for the first three fundamental modes.
Abstract: In this study, gradient cellular centresymmetric auxetic configurations are evaluated as potential cores for aeroengine fan blades, and optimized to reduce the dynamic response for the first three fundamental modes. Auxetic (negative Poisson’s ratio) re-entrant cellular beams are modeled, manufactured, and tested to assess their natural frequencies and mode shapes. Gradient versions of these beams with a varying internal cell angle are then designed to be incorporated as fillers in a baseline fan blade model. The optimized configurations of the gradient core lead to a substantial decrease of the mass of the fan blade, reduction of the dynamic modal displacements, and a lowering of the first three natural frequencies within the admissible frequency bandwidth.
Citations
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Journal ArticleDOI
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

Journal ArticleDOI
TL;DR: In this article, the authors focus on the topology-property relationship in three main classes of auxetic metamaterials, namely re-entrant, chiral, and rotating (semi-) rigid structures.
Abstract: The surge of interest in so-called “designer materials” during the last few years together with recent advances in additive manufacturing (3D printing) techniques that enable fabrication of materials with arbitrarily complex nano/micro-architecture have attracted increasing attention to the concept of mechanical metamaterials. Owing to their rationally designed nano/micro-architecture, mechanical metamaterials exhibit unusual properties at the macro-scale. These unusual mechanical properties could be exploited for the development of materials with advanced functionalities, with applications in soft robotics, biomedicine, soft electronics, acoustic cloaking, etc. Auxetic mechanical metamaterials are identified by a negative Poisson's ratio and are perhaps the most widely studied type of mechanical metamaterials. Similar to other types of mechanical metamaterials, the negative Poisson's ratio of auxetics is generally a direct consequence of the topology of their nano/micro-architecture. This paper therefore focuses on the topology–property relationship in three main classes of auxetic metamaterials, namely re-entrant, chiral, and rotating (semi-) rigid structures. While the deformation mechanisms in the above-mentioned types of structures and their relationship with the large-scale mechanical properties receive most attention, the emerging concepts in design of auxetics such as the use of instability in soft matter and origami-based structures are discussed as well. Furthermore, the data available in the literature regarding the elastic properties of auxetic mechanical metamaterials are systematically analyzed to identify the spread of Young's modulus–Poisson's ratio duos achieved in the auxetic materials developed to date.

428 citations

Journal ArticleDOI
TL;DR: In this paper, a comprehensive updated review of auxetic materials, their types and properties, and applications has been presented, and the design and modeling approaches of Auxetic structures are discussed.
Abstract: Material properties can be tailored through modification of their geometry or architecture. With this concept, a lot of smart materials, metamaterials, and smart structures have been developed. Auxetic materials and structures are a novel class of materials which exhibit an interesting property of negative Poisson's ratio. By virtue of the auxetic behavior, mechanical properties such as fracture toughness, indentation resistance, etc., can be improved. In order to exploit the interesting properties of auxetic materials, several potential applications of auxetic materials have been explored in medical, sports, automobile, defense, etc. Design and modeling of novel auxetic materials and structures is still on the way. Here, the article focuses upon the different aspects of auxetic materials and structures. A comprehensive updated review of auxetic materials, their types and properties, and applications has been presented. This paper also discusses the design and modeling approaches of auxetic structures.

378 citations

Journal ArticleDOI
TL;DR: In this paper, the auxetic effect is introduced, the range of auxetic materials is briefly reviewed, and research demonstrating benefits having potential in sports applications is highlighted, such as the use of the materials in impact protector devices exploiting better conformability for comfort and support, and enhanced energy absorption for lighter and/or thinner components.

226 citations

Journal ArticleDOI
TL;DR: In this article, the authors outline recent progress in the development of auxetic materials and structures, and their mechanical properties under quasi-static and dynamic loading are analysed and summarised.
Abstract: Different from conventional materials, materials with negative Poisson's ratios expand laterally when stretched longitudinally. Known as ‘auxetic’ materials, the effect means they possess particularly fascinating properties, which have recently attracted considerable attention in the literature. A range of auxetic materials has been discovered, theoretically designed and fabricated. Developments in additive manufacturing (AM) techniques enable fabrication of materials with intricate cellular architectures. This paper outlines recent progress in the development of auxetic materials and structures, and their mechanical properties under quasi-static and dynamic loading are analysed and summarised. Limited experimental studies on 3D printed auxetic materials and structures are given more attention, ahead of extensively finite element (FE) simulations. A special focus is dedicated to their large, plastic deformation behaviour and energy absorption performance, which should be stressed in their engineering applications; no review paper has yet been found regarding this. Finally, this paper provides an overview of current study limitations, and some future research is envisaged in terms of auxetic materials and structures, nano-auxetics and additive manufacturing.

214 citations

References
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Book
01 Aug 1988
TL;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
17 Sep 2011
TL;DR: In this article, the authors proposed a topology optimization by distribution of isotropic material for truss structures with anisotropic materials, based on the topology design of truss structure.
Abstract: 1 Topology optimization by distribution of isotropic material- 2 Extensions and applications- 3 Design with anisotropic materials- 4 Topology design of truss structures- 5 Appendices- 6 Bibliographical notes- References- Author Index

4,881 citations

Journal ArticleDOI
TL;DR: In this article, a theoretical and experimental investigation of a two-dimensional chiral honeycomb was conducted, and the honeycomb exhibits a Poisson's ratio of 1 for deformations in plane.

787 citations


"A Gradient Cellular Core for Aeroen..." refers background in this paper

  • ...Between the various cellular configurations, one can mention the chiral (or non-centresymmetric ones) (Prall and Lakes, 1996; Spadoni and Ruzzene, 2007; Martin et al., 2008; Abramovitch et al., 2010; Alderson et al., 2010; Bettini et al., 2010; Lorato et al., 2010; Miller et al., 2010; Tee et al., 2010) and star-shaped (Grima et al....

    [...]

  • ...Between the various cellular configurations, one can mention the chiral (or non-centresymmetric ones) (Prall and Lakes, 1996; Spadoni and Ruzzene, 2007; Martin et al., 2008; Abramovitch et al., 2010; Alderson et al., 2010; Bettini et al., 2010; Lorato et al., 2010; Miller et al., 2010; Tee et al.,…...

    [...]

Book
01 Jan 1997

508 citations


"A Gradient Cellular Core for Aeroen..." refers background in this paper

  • ...In aeroengine fan blades, a possible alternative to the use of a solid filler is the adoption of a cellular structure core, with its intrinsic lightweight and high specific transverse shear stiffness for increased bending stiffness, which makes the use of cellular structures a must for the design of general sandwich constructions (Zenkert, 1997)....

    [...]

  • ...The fact that two of the most sensitive regions to the optimization process are located at the root of the blade has some repercussions in the overall design of the fan component, due to the special designs to be put in place when classical honeycomb cores are joined together (Zenkert, 1997)....

    [...]

  • ...A significant effect of the multiscale levels between unit cells and dimensions of the honeycomb panels is also observed for the transverse shear moduli G13 and G23, which are between the most important parameters ruling the transverse bending of sandwich panels (Zenkert, 1997)....

    [...]

  • ...…to the use of a solid filler is the adoption of a cellular structure core, with its intrinsic lightweight and high specific transverse shear stiffness for increased bending stiffness, which makes the use of cellular structures a must for the design of general sandwich constructions (Zenkert, 1997)....

    [...]