Modulating poisson's ratio in flexible honeycombs by density and architecture gradations

Article Materials Science, Multidisciplinary

Multiscale Strain Field Characterization in Flexible Planar Auxetic Metamaterials with Rotating Squares

Kazi Zahir Uddin et al.

ADVANCED ENGINEERING MATERIALS (2023)

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Article Materials Science, Multidisciplinary

Density‐Dependent Impact Resilience and Auxeticity of Elastomeric Polyurea Foams

George Youssef et al.

ADVANCED ENGINEERING MATERIALS (2023)

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Article Chemistry, Multidisciplinary

Micro-Scale Auxetic Hierarchical Mechanical Metamaterials for Shape Morphing

K. K. Dudek et al.

Summary: In this paper, a novel hierarchical mechanical metamaterial is proposed that can exhibit a wide range of unusual auxetic behavior. The ability to control this behavior through geometric design parameters is demonstrated using experiments and computer simulations. The proposed structure is capable of shape morphing, making it suitable for various applications, including flexible electronics.

ADVANCED MATERIALS (2022)

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Article Mechanics

Mechanical properties of foam-filled hexagonal and re-entrant honeycombs under uniaxial compression

Hui Chen Luo et al.

Summary: Filling slow recovery foam into re-entrant honeycombs can prevent lateral buckling, increase stiffness and energy absorption capacity, showing promising potential in protective engineering.

COMPOSITE STRUCTURES (2022)

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Article Mechanics

An optimization approach to design deformation patterns in perforated mechanical metamaterials using distributions of Poisson's ratio-based unit cells

Jianfei Yao et al.

Summary: A method is proposed to design deformation patterns in perforated structures by optimizing the distribution of Poisson's ratio-based unit cells. By optimizing the permutation and combination of homogenized local Poisson's ratios, a two-dimensional perforated structure that satisfies the required deformation pattern can be obtained. Simulation and experiments demonstrate that this approach can provide controllable shape changes in 2D perforated mechanical metamaterials under uniaxial tensile loading.

COMPOSITE STRUCTURES (2022)

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Review Engineering, Multidisciplinary

Manufacturing, characteristics and applications of auxetic foams: A state-of-the-art review

Wei Jiang et al.

Summary: Auxetic foams exhibit unique mechanical properties and multiphysics characteristics, making them potential candidates for applications in biomedicine, aerospace, and smart sensing. However, challenges such as complex fabrication and lacking stability hinder their practical applications, requiring further research and development to overcome these barriers.

COMPOSITES PART B-ENGINEERING (2022)

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Article Materials Science, Multidisciplinary

Flexible planar metamaterials with tunable Poisson's ratios

Nicholas Pagliocca et al.

Summary: This research focuses on the design, fabrication, and mechanical characterization of flexible, planar mechanical metamaterials with tunable properties. By introducing different geometric perforations, the structures exhibit adjustable mechanical behavior and a wide range of Poisson's ratios. The study highlights the correlation between perforation configurations and auxetic response, and proposes a practical strategy for activating a self-strengthening mechanism in the structures. It also demonstrates the feasibility of fabricating planar flexible structures with controllable Poisson's ratios through spatial adjustment of perforations.

MATERIALS & DESIGN (2022)

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Article Materials Science, Multidisciplinary

Composite-inspired multilattice metamaterial structure: An auxetic lattice design with improved strength and energy absorption

Bikram Jyoti Sahariah et al.

Summary: In this study, a novel dual-phase lattice structure called 'multilattice' structure was designed and fabricated. The multilattice structure consists of a 3D reentrant auxetic lattice as the matrix and a body-centered-tetragonal lattice with vertical struts as reinforcements. Numerical simulations and quasi-static compression tests were conducted to investigate the mechanical response and deformation mechanics of the multilattice structures. The results showed that the multilattice structures exhibited superior strength and stiffness compared to the parent 3D reentrant lattice, while maintaining the negative Poisson's ratio behavior. The study also found that the mechanical properties of the multilattice structures could be tailored by adjusting the volume fraction and type of reinforcements.

MATERIALS TODAY COMMUNICATIONS (2022)

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Article Engineering, Multidisciplinary

3D Zero Poisson's Ratio Honeycomb Structure for Morphing Wing Applications

Xiaobo Gong et al.

Summary: A novel 3D Zero Poisson's Ratio (ZPR) honeycomb structure is designed to meet the flexible deformation requirements of morphing aircraft. Pneumatic muscle fibers are introduced as flexible actuators to drive the active deformation of the 3D ZPR honeycomb. The experimental results show the potential of this 3D ZPR structure for morphing wing applications.

BIOMIMETICS (2022)

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Article Mechanics

In-Plane mechanical and failure responses of honeycombs with syntactic foam cell walls

Nicholas Pagliocca et al.

Summary: This work investigates the load-bearing and energy absorption capacities of hexagonal honeycombs with syntactic cell walls and spatial gradation of cell densities. The results show that the energy absorption capacity of the structures can be improved by incorporating microballoons into the cell struts and controlling their spatial distribution. The findings also reveal that the spatial gradation of cell densities offers notable improvement to the energy absorption performance and provides a mechanism to lower structural density while achieving high mechanical performance.

COMPOSITE STRUCTURES (2022)

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Article Materials Science, Composites

Out-of-plane load-bearing and mechanical energy absorption properties of flexible density-graded TPU honeycombs

Ibnaj Anamika Anni et al.

Summary: This study investigates the mechanical response and strain energy absorption characteristics of honeycomb structures with different cell wall thicknesses under out-of-plane loading conditions. The results show that density-graded structures exhibit superior load-bearing response at large deformation conditions and outperform uniform density structures in terms of strain energy absorption at small deformation conditions. These findings highlight the significance of density gradation in developing honeycomb structures with highly tailorable mechanical properties.

COMPOSITES PART C: OPEN ACCESS (2022)

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Article Materials Science, Multidisciplinary

A multiscale experimental approach to characterize micro-to-macro transition length scale in polymer foams

Behrad Koohbor et al.

Summary: This study quantitatively characterized the micro-to-macro transition length scale in polymeric foams using an experimental-statistical approach, showing that this transition is a function of material density.

MECHANICS OF MATERIALS (2021)

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Article Mechanics

Two-dimensional graded metamaterials with auxetic rectangular perforations

Jianfei Yao et al.

Summary: This study investigates the in-plane uniaxial tensile mechanical properties of two-dimensional graded rectangular perforations metamaterials using numerical homogenization finite element approaches benchmarked by experimental results. The metamaterial configuration is based on graded patterns of center-symmetric perforated cells that can exhibit an auxetic behavior. The overall stiffness behavior of the graded perforated metamaterial plates features a higher degree of compliance that depends on both the geometries of the cells of the graded areas and the graded pattern used.

COMPOSITE STRUCTURES (2021)

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Review Engineering, Manufacturing

On the application of additive manufacturing methods for auxetic structures: a review

Athul Joseph et al.

Summary: Auxetic structures are unique structural components with a negative Poisson's ratio, requiring specialized manufacturing processes for realization. Additive manufacturing techniques play a crucial role in fabricating auxetic structures, providing faster and more precise manufacturing methods. A detailed discussion of various AM techniques offers insights into the current research status of auxetic structures.

ADVANCES IN MANUFACTURING (2021)

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Article Physics, Condensed Matter