Atomistic modeling at experimental strain rates and timescales

Yan, Xiang-Ping; Cao, Penghui; Wen, Tao; Sharma, Pradeep; Park, Harold S.

doi:10.1088/0022-3727/49/49/493002

Cited by 24 publications

(16 citation statements)

References 76 publications

(155 reference statements)

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“…In horizontal direction, the spring connected to VL makes the tip to move, and the speed of VL is constant of

. We would like to remark that this speed may be much faster than the experimental settings, and to give a realistic evaluation of speed effect (which is not included in current study), time-scaling atomistic simulation approaches could be adopted [ 35 ]. In the friction model, the size of MXene flakes we used were 20.3 nm × 17.0 nm and it contained around 88,000 atoms.…”

Section: Methodsmentioning

confidence: 99%

“…Due to the time-scale bottleneck of the MD calculation, some parameters, such as sliding velocity, are still difficult to match using an atomic force microscopy (AFM) experiment [ 32 ]. Some researchers adopt time-scale atomistic approaches to extend the timescale in the atomistic simulation on models not limited in friction or indentation [ 33 , 34 , 35 , 36 ]. It is undoubted that computational methods can provide guidance for experiments and obtain an insight into the microscopic mechanisms of MXenes.…”

Section: Introductionmentioning

confidence: 99%

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The Effects of the Temperature and Termination(-O) on the Friction and Adhesion Properties of MXenes Using Molecular Dynamics Simulation

et al. 2022

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Two-dimensional transition metal carbides and nitrides (MXenes) are widely applied in the fields of electrochemistry, energy storage, electromagnetism, etc., due to their extremely excellent properties, including mechanical performance, thermal stability, photothermal conversion and abundant surface properties. Usually, the surfaces of the MXenes are terminated by –OH, –F, –O or other functional groups and these functional groups of MXenes are related surface properties and reported to affect the mechanical properties of MXenes. Thus, understanding the effects of surface terminal groups on the properties of MXenes is crucial for device fabrication as well as composite synthesis using MXenes. In this paper, using molecular dynamics (MD) simulation, we study the adhesion and friction properties of Ti2C and Ti2CO2, including the indentation strength, adhesion energy and dynamics of friction. Our indentation fracture simulation reveals that there are many unbroken bonds and large residual stresses due to the oxidation of oxygen atoms on the surface of Ti2CO2. By contrast, the cracks of Ti2C keep clean at all temperatures. In addition, we calculate the elastic constants of Ti2C and Ti2CO2 by the fitting force–displacement curves with elastic plate theory and demonstrate that the elastic module of Ti2CO2 is higher. Although the temperature had a significant effect on the indentation fracture process, it hardly influences maximum adhesion. The adhesion energies of Ti2C and Ti2CO2 were calculated to be 0.3 J/m2 and 0.5 J/m2 according to Maugis–Dugdale theory. In the friction simulation, the stick-slip atomic scale phenomenon is clearly observed. The friction force and roughness (Ra) of Ti2C and Ti2CO2 at different temperatures are analyzed. Our study provides a comprehensive insight into the mechanical behavior of nanoindentation and the surface properties of oxygen functionalized MXenes, and the results are beneficial for the further design of nanodevices and composites.

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“…In horizontal direction, the spring connected to VL makes the tip to move, and the speed of VL is constant of

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effects of the Temperature and Termination(-O) on the Friction and Adhesion Properties of MXenes Using Molecular Dynamics Simulation

et al. 2022

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“…To realize the slow loading rate, we adopted a time-scaling approach based on a potential energy surface sampling method, the so-called autonomous basin climbing approach (ABC) [28,29]. Further details of the approach may be found in the papers of its originators [30,31] and several others [32,33]. Accordingly, we provide only a highly abbreviated description here.…”

Section: Approachmentioning

confidence: 99%

An Atomistic Perspective on the Effect of Strain Rate and Lithium Fraction on the Mechanical Behavior of Silicon Electrodes

Darbaniyan

Yan

Sharma

2019

Journal of Applied Mechanics

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The process of charging and discharging of lithium-ion batteries results in the periodic intercalation and ejection of lithium ions in the anode material. High-capacity anode materials that are of significant interest for next-generation batteries, such as silicon, undergo large deformation during this process. The ensuing electro-chemo-mechanical stresses and accompanying microstructural changes lead to a complex state of inelastic deformation and damage in the silicon electrode that causes a significant capacity loss within just a few cycles. In this study, we attempt to understand, from an atomistic viewpoint, the mechanisms underlying the plasticity behavior of Si-anode as a function of lithiation. Conventional molecular dynamics simulations are of limited use since they are restricted to loading rates in the order of 108 s−1. Practical charging-discharging rates are several orders of magnitude slower, thus precluding a realistic atomistic assessment of the highly rate-dependent mechanical behavior of lithiated silicon anodes via conventional molecular dynamics. In this work, we use a time-scaling approach that is predicated on the combination of a potential energy surface sampling method, minimum energy pathway, kinetic Monte Carlo, and transition state theory, to achieve applied strain rates as low as 1 s−1. We assess and compare the atomistic mechanisms of plastic deformation in three different lithium concentration structures: LiSi2, LiSi, and Li15Si4 for various strain-rates. We find that the strain rate plays a significant role in the alteration of the deformation and damage mechanisms including the evolution of the plastic deformation, nucleation of shear transformation zone, and void nucleation. Somewhat anomalously, LiSi appears to demonstrate (comparatively) the least strain rate sensitivity.

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“…However, a huge gap in the timescale between simulations and experiments [ 32 ] always results in discrepancies in learning the rate-dependent mechanical response, especially when the deformation mechanisms show rate-dependency. To overcome this shortage of molecular dynamics methods, simulations covering timescales over ten orders of magnitude should be considered [ 33 ]. Although there are abundant literatures about the rate-dependent mechanical response of silicon, most of these studies have focused on amorphous silicon structures or surface indentation, resulting in a relatively poor understanding of some typical silicon structures, such as the monocrystalline silicon wafer and silicon nanowire [ 34 , 35 ].…”

Section: Introductionmentioning

confidence: 99%

Revisiting the Rate-Dependent Mechanical Response of Typical Silicon Structures via Molecular Dynamics

Liu

Wan

et al. 2022

Nanomaterials

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Strain rate is a critical parameter in the mechanical application of nano-devices. A comparative atomistic study on both perfect monocrystalline silicon crystal and silicon nanowire was performed to investigate how the strain rate affects the mechanical response of these silicon structures. Using a rate response model, the strain rate sensitivity and the critical strain rate of two structures were given. The rate-dependent dislocation activities in the fracture process were also discussed, from which the dislocation nucleation and motion were found to play an important role in the low strain rate deformations. Finally, through the comparison of five equivalent stresses, the von Mises stress was verified as a robust yield criterion of the two silicon structures under the strain rate effects.

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Atomistic modeling at experimental strain rates and timescales

Cited by 24 publications

References 76 publications

The Effects of the Temperature and Termination(-O) on the Friction and Adhesion Properties of MXenes Using Molecular Dynamics Simulation

The Effects of the Temperature and Termination(-O) on the Friction and Adhesion Properties of MXenes Using Molecular Dynamics Simulation

An Atomistic Perspective on the Effect of Strain Rate and Lithium Fraction on the Mechanical Behavior of Silicon Electrodes

Revisiting the Rate-Dependent Mechanical Response of Typical Silicon Structures via Molecular Dynamics

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