Atomistic mechanisms of crack nucleation and propagation in amorphous silica

Hao, Tengyuan; Hossain, Zubaer M.

doi:10.1103/physrevb.100.014204

Cited by 22 publications

(8 citation statements)

References 83 publications

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“…The contribution of ductility in a-SiO 2 at nanoscale is caused by a portion of energy from the stored strain energy that is converted into heat or unrecoverable inelastic deformation [28]. Note that, to simplify the analysis and to be similar to other RMD studies [15,28,35,44], plane stress conditions were used in the x-y plane by setting L z L x and L z L y for this study. An accurate analysis, as well as a comparison in anisotropy of a-SiO 2 under different boundary and loading conditions will be a part of our future work, where the dimensions in all the directions remain the same.…”

Section: Poisson's Ratio and Isotropymentioning

confidence: 99%

“…For instance, Heino et al found that for relatively large systems (>10 5 atoms) the moduli of copper turned out to be independent of the system size [14]. In another study, it was revealed that both strength and toughness of silica glass converge well for domains larger than 3×10 5 atoms [15]. However, there is still a knowledge gap in the size effect associated with different boundary and loading conditions.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Domain Size, Boundary, and Loading Conditions on Mechanical Properties of Amorphous Silica: A Reactive Molecular Dynamics Study

Reeder

Damone

et al. 2019

Nanomaterials

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Mechanical properties are very important when choosing a material for a specific application. They help to determine the range of usefulness of a material, establish the service life, and classify and identify materials. The size effect on mechanical properties has been well established numerically and experimentally. However, the role of the size effect combined with boundary and loading conditions on mechanical properties remains unknown. In this paper, by using molecular dynamics (MD) simulations with the state-of-the-art ReaxFF force field, we study mechanical properties of amorphous silica (e.g., Young’s modulus, Poisson’s ratio) as a function of domain size, full-/semi-periodic boundary condition, and tensile/compressive loading. We found that the domain-size effect on Young’s modulus and Poisson’s ratio is much more significant in semi-periodic domains compared to full-periodic domains. The results, for the first time, revealed the bimodular and anisotropic nature of amorphous silica at the atomic level. We also defined a “safe zone” regarding the domain size, where the bulk properties of amorphous silica can be reproducible, while the computational cost and accuracy are in balance.

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Section: Poisson's Ratio and Isotropymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Domain Size, Boundary, and Loading Conditions on Mechanical Properties of Amorphous Silica: A Reactive Molecular Dynamics Study

Reeder

Damone

et al. 2019

Nanomaterials

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“…Unfortunately experimental techniques do not allow to probe these quantities with high precision since the process zone near the crack tip in which energy dissipation occurs has been reported to have a size of less than 10 nm [28,29], i.e., is at the resolution limit of typical experimental probes. Recent atomistic simulations have allowed to gain some insight into atomic-scale properties, such as the dissipation of energy in the vicinity of the crack tip using the atomistic J-integral approach [30][31][32], as well as the heterogeneities in local structure and mechanical properties and the correlations between them [22,27,[33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Fracture of silicate glasses: Micro-cavities and correlations between atomic-level properties

Zhang¹,

Ispas²,

Kob³

2022

Preprint

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We use large-scale simulations to investigate the dynamic fracture of silica and sodium-silicate glasses under uniaxial tension. The stress-strain curves demonstrate that silica glass is brittle whereas the glasses rich in Na show pronounced ductility. A strong composition dependence is also seen in the crack velocity which is on the order of 1800 m/s for glasses with low Na concentration and decreases to 700 m/s if the concentration is high. We find that during the fracture of Narich glasses very irregular cavities as large as 3-4 nm form ahead of the crack front, indicating the presence of nanoductility in these glasses. Before fracture occurs, the local composition, structure, and mechanical properties are heterogeneous in space and show a strong dependence on the applied strain. Further analysis of the correlations between these local properties allows to obtain a better microscopic understanding of the deformation and fracture of glasses and how the local heating close to the crack tip, up to several hundred degrees, permits the structure to relax.

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“…However the main disadvantage is that the discrete nature of crystalline materials can not be accurately captured in continuum mechanics, and therefore it is hard to describe the effects of microstructure characters. At microscopic scale, with the advent of numerical techniques and computing power, the models based directly on atomic information such as molecular dynamics (MD) simulation could provide accurate descriptions of crystalline materials with billions of atoms [7,1,55,26]. But the limitations on both length and time scales are still always be found due to its expensive computation cost.…”

mentioning

confidence: 99%

On the Cauchy-Born approximation at finite temperature for alloys

Dai¹,

Wang²,

Yang³

et al. 2021

DCDS-B

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<p style='text-indent:20px;'>In this paper, we present the procedure of generalization and implementation of the Cauchy-Born approximation to the calculation of stress at finite temperature for alloy system in which the effects of inner displacement should be incorporated. With the help of quasi-harmonic approximation, a closed form of the first Piola-Kirchhoff stress is derived as a summation of pure deformation contribution and linear term due to thermal effects. For alloy system with periodic boundary condition, a further simplified formulation of stress based on some invariance constraints is derived in reciprocal space by using Fourier transformation, in which the temperature effect can be efficiently taking account. Several numerical examples are performed for various crystalline systems to validate our generalization procedure of finite temperature Cauchy-Born (FTCB) method for alloy.</p>

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Atomistic mechanisms of crack nucleation and propagation in amorphous silica

Cited by 22 publications

References 83 publications

Effect of Domain Size, Boundary, and Loading Conditions on Mechanical Properties of Amorphous Silica: A Reactive Molecular Dynamics Study

Effect of Domain Size, Boundary, and Loading Conditions on Mechanical Properties of Amorphous Silica: A Reactive Molecular Dynamics Study

Fracture of silicate glasses: Micro-cavities and correlations between atomic-level properties

On the Cauchy-Born approximation at finite temperature for alloys

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