Magic auxeticity angle of graphene

Hou, Jie; Deng, Binghui; Zhu, Hanxing; Lan, Yucheng; Shi, Yunfeng; De, Suvranu; Liu, Li; Chakraborty, Pritam; Gao, Fei; Peng, Qing

doi:10.1016/j.carbon.2019.04.057

Cited by 39 publications

(25 citation statements)

References 34 publications

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“…In addition, to avoid size effects, all the simulations were performed on PSI-graphene sheets with similar size. According to the study of graphene multi-angle stretching [12], we constructed the model of PSI-graphene sheets with about 18,000 atoms. In all simulations, periodic boundary conditions along the x and y directions and fixed boundary conditions along the z direction were used.…”

Section: Methodsmentioning

confidence: 99%

“…Most solid materials shrink transversely when they are stretched in the longitudinal direction, resulting in a positive Poisson's ratio (PPR) value. However, the abnormal ones, known as auxetics, will exhibit transverse expansion [12]. The ultimate strength is the maximum stress of the material at breaking point and the fracture strain is the strain at the time of failure of the material.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Angle, Temperature and Vacancy Defects on Mechanical Properties of PSI-Graphene

Xie

Sun

et al. 2019

Crystals

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The PSI-graphene, a two-dimensional structure, was a novel carbon allotrope. In this paper, based on molecular dynamics simulation, the effects of stretching direction, temperature and vacancy defects on the mechanical properties of PSI-graphene were studied. We found that when PSI-graphene was stretched along 0° and 90° at 300 K, the ultimate strength reached a maximum of about 65 GPa. And when stretched along 54.2° and 155.2° at 300 K, the Young’s modulus had peaks, which were 1105 GPa and 2082 GPa, respectively. In addition, when the temperature was raised from 300 K to 900 K, the ultimate strength in all directions was reduced. The fracture morphology of PSI-graphene stretched at different angles was also shown in the text. In addition, the number of points removed from PSI-graphene sheet also seriously affected the tensile properties of the material. It was found that, compared with graphene, PSI-graphene didn’t have the negative Poisson’s ratio phenomenon when it was stretched along the direction of 0°, 11.2°, 24.8° and 34.7°. Our results provided a reference for studying the multi-angle stretching of other carbon structures at various temperatures.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Angle, Temperature and Vacancy Defects on Mechanical Properties of PSI-Graphene

Xie

Sun

et al. 2019

Crystals

Self Cite

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“…The method of molecular simulations is well established and it is an indispensable tool for various investigations in nowadays. [7,20,[30][31][32] For the present study, we deal with seven distinct alkane glasses as listed in Table 1. The molecular structures were created using a method proposed by Müller et al [33] It essentially consists of a heuristic search algorithm in the space of torsion angle that automatically delivers correct conformational statistics of the chains and maintain rotational-isomericstate probabilities.…”

Section: Molecular Simulationsmentioning

confidence: 99%

Reduced Plastic Dilatancy in Polymer Glasses

Peng

Deng

Utz

2020

Macro Theory & Simulations

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Amorphous solids in general exhibit a volume change during plastic deformation due to microstructure change during plastic relaxation. Here the deformation dilatancy of alkane polymer glasses upon shearing is investigated using molecular static simulations at zero temperature and pressure. The dilatancy of linear alkane chains has been quantified as a function of strain and chain length. It is found that the system densities decrease linearly with respect to strain after yield point. In addition, dilatability decreases considerably with increasing chain length, suggesting enhanced cooperation of different deformation mechanisms. An analytic model is introduced for dilatability based on the atomistic study. The entanglement chain length is predicted as 43 for alkane polymers from the model, agreeing well with experiments. The study provides insights of correlations of the physical properties and chain length of polymers which might be useful in material design and applications of structural polymers.

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“…The shrinkage area becomes denser to increase indentation resistance [21][22][23]. To date a wide range of materials have been modified to be auxetic including polymers [24], metals [12,25], ceramics [26][27][28], composites [29,30], and fibres [31,32]. In nature, these materials can be found in black phosphorus [33] or biological tissues [34].…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study of auxetic sandwich panels on 160 grams of PE4 blast loading

Arifurrahman

Critchley

Horsfall

2020

Jnl of Sandwich Structures & Materials

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Mines, specifically as Anti-Tank (AT) mines are a significant threat for defence vehicles. While approaches such as v-shaped hulls are currently used to deflect the blast products from such threats, such a solution is not always usable when hull standoff is limited. As such the development of a low profile, energy absorbing solution is desirable. One approach that has potential to achieve these requirements are sandwich panels. While sandwich panel cores can be constructed from various materials, one material of particular interest are auxetics. Auxetic are materials that exhibit a negative Poisson’s ratio. This material has potential to be an efficient an impact energy absorber by increasing stiffness at local deformation by gathering mass at the impact location. This study investigates the effectiveness of novel auxetic core infills alongside three other panel types (monolithic, air gap, polymer foam sandwich) against buried charges. 160 grams of PE4 were buried in 100 mm depth and 500 mm stand off the target. Laser and High Speed Video (HSV) system were used to capture the deflection-time profile and load cell sensors were used to record the loading profile received by the panels. Experimental works were compared with numerical model. Explicit model were generated in LSDYNA software as ‘initial impulse mine’ keyword. The result found that the auxetic and foam core panels were effective in reducing peak structural loading and impulse by up to 33% and 34% respectively. Air-filled panels were the most effective to reduce the deflection of the rear of the plate, however variation between capture methods (HSV and Laser system) were reported, while numerical modelling provided comparable plate deflections responses. When normalised against panel weight, the air filled panels were experimentally the most efficient per unit mass system with the auxetics being the least effective.

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Magic auxeticity angle of graphene

Cited by 39 publications

References 34 publications

Effect of Angle, Temperature and Vacancy Defects on Mechanical Properties of PSI-Graphene

Effect of Angle, Temperature and Vacancy Defects on Mechanical Properties of PSI-Graphene

Reduced Plastic Dilatancy in Polymer Glasses

Experimental and numerical study of auxetic sandwich panels on 160 grams of PE4 blast loading

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