Bending-Dominated Auxetic Materials for Wearable Protective Devices Against Impact

Faraci, David; Driemeier, Larissa; Comi, Claudia

doi:10.1007/s40870-020-00284-2

Cited by 13 publications

(7 citation statements)

References 25 publications

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“…The design of an auxetic structure made up of four connected re-entrant cells forming a closed system may resemble an automotive suspension system. Similar three-dimensional structures based on bow-tie elements have already been described in a number of research papers [26,[40][41][42][43][44][45][46]. The combined individual cells, forming a two-dimensional structure, can easily be transformed into a three-dimensional structure that exhibits auxetic behaviour.…”

Section: Discussion Of Symmetrical Cell Structurementioning

confidence: 65%

Experimental Study of Auxetic Structures Made of Re-Entrant (“Bow-Tie”) Cells

Plewa,

Płońska,

Feliksik

et al. 2024

Materials

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This article presents a study of metamaterial structures that exhibit auxetic properties. This unusual phenomenon of simultaneous orthogonal expansion of the metamaterial in tension, and vice versa in compression, with vertical and horizontal contraction, is explored for structures made of re-entrant unit cells. The geometry of such structures is analysed in detail, and the relationships are determined by the value of the Poisson’s ratio. It is shown that the Poisson’s ratio depends not only on the geometry of the unit cell but also on the degree of strain. Depending on the dimensions of the structure’s horizontal and inclined struts, the limit values are determined for the angle between them. By creating physical structures made of re-entrant cells, it is demonstrated that the mechanism of change in the structure’s dimensions is not due to the hinging but to the bending of the struts. The experimental section contains the results of compression tests of a symmetrical structure and tensile tests of a flat mesh structure. In the case of the mesh structure, a modification of the re-entrant cells was used to create arched strut joints. This modification makes it possible to obtain greater elongation of the mesh structure and larger NPR values.

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Section: Discussion Of Symmetrical Cell Structurementioning

confidence: 65%

Experimental Study of Auxetic Structures Made of Re-Entrant (“Bow-Tie”) Cells

Plewa,

Płońska,

Feliksik

et al. 2024

Materials

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“…This occurs e.g. for the proposal in Faraci et al (2021) of a wearable protective mask against impact having a layered structure with a metamaterial core. Modeling the entire mask with the actual microstructure would require prohibitive computational times.…”

Section: Protective Auxetic Sandwich Platementioning

confidence: 99%

“…Modeling the entire mask with the actual microstructure would require prohibitive computational times. As in Faraci et al (2021), we hence simulate by finite element analysis the impact of a rigid sphere against just a small portion of the sandwich structure (Figure 4a) composed of two homogeneous layers and the auxetic material core shown in Figure 1a, of 5 × 5 × 4 cells made of a linear-elastic material.…”

Section: Protective Auxetic Sandwich Platementioning

confidence: 99%

“…These materials have a negative Poisson's ratio, ν, which means that they expand in the lateral direction when stretched longitudinally. This property leads to improved indentation resistance, thermal shock resistance, impact performance (Faraci et al (2021), Madke and Chowdhury (2020)), fracture toughness and fatigue behaviour in tension (Bezazi and Scarpa (2009)). Figure 1a shows an example of a 3-dimensional lattice of an auxetic metamaterial, with the unit cell shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Homogenization and metamaterials: an effective alliance

Comi¹

2022

Proceedings of the 8th International Symposium on Solid Mechanics

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The fast growing field of metamaterials opens a number of new opportunities and applications but, at the same time, introduces many challenges in the design and modeling. The two scale asymptotic homogenization appears as a promising tool for the design and optimization of systems composed of metamaterials. In this contribution, we discuss the role of homogenization in the development of practical applications of metamaterials. Focus will be in particular on two significant examples: the optimization of auxetic metamaterials for energy absorption and the design of a system for energy localization that includes locally resonant materials. In both cases, the metamaterial is substituted with an equivalent homogenized continuum allowing for a fast parametric optimization and leading to a significant computational advantage.

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“…Auxetic structures possess the novel property of a negative Poisson's ratio (PR) [9, 25,26]. Negative PR materials are well-known for their excellent of lateral contraction behaviour and resistance to expansion when exposed to compression and tension, respectively [27][28][29][30][31][32][33][34]. While common natural materials, also referred to as positive PR materials, exhibit swell behaviour perpendicular to compressive loading and contraction behaviour under tensile loading, as given in Figure 1 [25,35], these auxetic materials provide a wide range of engineering advantages with superior mechanical properties such as shear resistance [9], higher fracture toughness, lower fatigue crack propagation [36][37][38][39][40][41], vibration mitigation [42], indentation resistance [43], crashworthiness [44,45], light weight [46], energy absorption [47,48], etc.…”

Section: Introductionmentioning

confidence: 99%

Local Failure Modes and Critical Buckling Loads of a Meta-Functional Auxetic Sandwich Core for Composite Bridge Bearing Applications

Sengsri

Kaewunruen

2021

Applied Sciences

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This paper presents a novel meta-functional auxetic unit (MFAU) cell designed to improve performance and weight ratio for structural bridge bearing applications. Numerical investigations were conducted using three-dimensional finite element models validated by experimental results. The validated models were exposed to compression and buckling actions to identify structural failure modes, with special attention placed on the global behaviours of the meta-functional auxetic (MFA) composite bridge bearing. This bearing uses an unprecedented auxetic sandwich core design consisting of multiple MFAU cells. Numerical predictions of the elastic local critical buckling loads of the MFAU cell were in excellent agreement with both the analytical and experimental results, with an observed discrepancy of less than 1%. These results demonstrate that local buckling failures of MFAU cells can potentially be incurred prior to yielding under compression due to their slenderness ratios. Surprisingly, the designed sandwich core used in the MFA composite bridge bearing model can mimic an auxetic structure with significant crashworthiness, implying that this novel core composite structure can be tailored for structural bridge bearing applications. Parametric studies were thus carried out in order to enrich our insight into the MFA composite elements. These insights, stemming from both experimental and numerical studies, enable a novel design paradigm for MFAU that can significantly enhance the structural performance of MFA composite bridge bearings in practice.

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Bending-Dominated Auxetic Materials for Wearable Protective Devices Against Impact

Cited by 13 publications

References 25 publications

Experimental Study of Auxetic Structures Made of Re-Entrant (“Bow-Tie”) Cells

Experimental Study of Auxetic Structures Made of Re-Entrant (“Bow-Tie”) Cells

Homogenization and metamaterials: an effective alliance

Local Failure Modes and Critical Buckling Loads of a Meta-Functional Auxetic Sandwich Core for Composite Bridge Bearing Applications

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