New theory for Mode I crack-tip dislocation emission

Andric, Predrag; Curtin, W.A.

doi:10.1016/j.jmps.2017.06.006

Cited by 78 publications

(53 citation statements)

References 35 publications

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“…The method is expected to be generally applicable to any system where localised chemical processes are driven by long range elastic fields. For example, the technique could be applied to provide ab initio mechanistic insight into the dynamics of three-dimensional crack fronts, where fracture proceeds through kink formation and advance 44 , or to provide a QM-based analogue of the Rice-Thomson criterion for the transition from brittle cleavage to dislocation emission 46,47 . We wish to define a position scaling α and energy scaling β on the classical system to match the bulk moduli and lattice constant of the quantum system.…”

Section: Discussionmentioning

confidence: 99%

Computing energy barriers for rare events from hybrid quantum/classical simulations through the virtual work principle

Swinburne

Kermode

2017

Phys. Rev. B

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Hybrid quantum/classical techniques can flexibly couple ab initio simulations to an empirical or elastic medium to model materials systems that cannot be contained in small periodic supercells. However, due to electronic non-locality a total energy cannot be defined, meaning energy barriers cannot be calculated. We provide a general solution using the principle of virtual work in a modified nudged elastic band algorithm. Our method enables the first ab initio calculations of the kink formation energy for 100 edge dislocations in molybdenum and lattice trapping barriers to brittle fracture in silicon.arXiv:1709.10499v1 [cond-mat.mtrl-sci]

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Section: Discussionmentioning

confidence: 99%

Computing energy barriers for rare events from hybrid quantum/classical simulations through the virtual work principle

Swinburne

Kermode

2017

Phys. Rev. B

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“…Molecular statics simulations of the tensile deformation of Cu and Ni single crystal nanoplates with an edge crack were conducted at 0 K using the open source molecular dynamics (MD) program called the large-scale atomic/molecular massively parallel simulator (LAMMPS) [20]. The MS technique was used instead of MD method with an aim to avoid the extreme high strain rates associated with MD simulations [21,22]. Molecular statics simulations have been widely used to study crack growth behavior in solids [21,22].…”

Section: Methodsmentioning

confidence: 99%

“…The MS technique was used instead of MD method with an aim to avoid the extreme high strain rates associated with MD simulations [21,22]. Molecular statics simulations have been widely used to study crack growth behavior in solids [21,22]. The atomic configurations were visualized by AtomEye [23].…”

Section: Methodsmentioning

confidence: 99%

R-curve Evaluation of Copper and Nickel Single Crystals Using Atomistic Simulations

2018

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The technique of molecular statics (MS) simulation was employed to determine the crack growth resistance curve of Cu and Ni single crystals. Copper and Ni single crystal nanoplates with an edge crack subjected to a tensile displacement were simulated. Stress-displacement curves and snapshots of the atomic configuration corresponding to different displacement levels were presented to elucidate the deformation mechanism. It was observed that the edge crack propagated step by step in a brittle manner, and the amount of crack growth at each step was half the lattice parameter. Through an energy consideration, the critical strain energy release rate at the onset of crack propagation and the crack growth resistance were calculated. The crack growth resistance is larger than the critical strain energy release rate because of the crack growth effect.

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“…Underlying atomistic details are especially important when it comes to studies on fracture and damage [28]. A new theory is formulated in [29] for dislocation emission under mode I loading using molecular statics simulations. A multiscale method is developed in [30] for examining fracture of polycrystals by coupling molecular dynamics and mesoscale peridynamics.…”

Section: Small Scale Matters: Importance Of Atomistic Simulationsmentioning

confidence: 99%

Application of artificial neural networks for the prediction of interface mechanics: a study on grain boundary constitutive behavior

Fernández

Rezaei

Mianroodi

et al. 2020

Adv. Model. and Simul. in Eng. Sci.

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The present work aims at the identification of the effective constitutive behavior of 5 aluminum grain boundaries (GB) for proportional loading by using machine learning (ML) techniques. The input for the ML approach is high accuracy data gathered in challenging molecular dynamics (MD) simulations at the atomic scale for varying temperatures and loading conditions. The effective traction-separation relation is recorded during the MD simulations. The raw MD data then serves for the training of an artificial neural network (ANN) as a surrogate model of the constitutive behavior at the grain boundary. Despite the extremely fluctuating nature of the MD data and its inhomogeneous distribution in the traction-separation space, the ANN surrogate trained on the raw MD data shows a very good agreement in the average behavior without any data-smoothing or pre-processing. Further, it is shown that the trained traction-separation ANN captures important physical properties and is able to predict traction values for given separations not contained in the training data. For example, MD simulations show a transition in traction-separation behaviour from pure sliding mode under shear load to combined GB sliding and decohesion with intermediate hardening regime at mixed load directions. These changes in GB behaviour are fully captured in the ANN predictions. Furthermore, by construction, the ANN surrogate is differentiable for arbitrary separation and also temperature, such that a thermo-mechanical tangent stiffness operator can always be evaluated. The trained ANN can then serve for large-scale FE simulation as an alternative to direct MD-FE coupling which is often infeasible in practical applications.

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New theory for Mode I crack-tip dislocation emission

Cited by 78 publications

References 35 publications

Computing energy barriers for rare events from hybrid quantum/classical simulations through the virtual work principle

Computing energy barriers for rare events from hybrid quantum/classical simulations through the virtual work principle

R-curve Evaluation of Copper and Nickel Single Crystals Using Atomistic Simulations

Application of artificial neural networks for the prediction of interface mechanics: a study on grain boundary constitutive behavior

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