From yield to fracture, failure initiation captured by molecular simulation

Brochard, Laurent; Tejada, Ignacio G.; Sab, Karam

doi:10.1016/j.jmps.2016.05.005

Cited by 16 publications

(9 citation statements)

References 59 publications

(89 reference statements)

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“…Yin et al [163] found that a local bond strength failure criterion seems to perform better than the Griffith criterion for a graphene sheet containing a crack shorter than 10 nm. Brochard et al [164] found a transition from energy-governed (Griffith criterion) to stress-governed failure in graphene, and proposed a composite failure criterion including both stress and energy.…”

Section: Strength and Toughnessmentioning

confidence: 99%

A review on mechanics and mechanical properties of 2D materials—Graphene and beyond

Akinwande

Brennan

Bunch

et al. 2017

Extreme Mechanics Letters

1,048

649

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Since the first successful synthesis of graphene just over a decade ago, a variety of twodimensional (2D) materials (e.g., transition metal-dichalcogenides, hexagonal boron-nitride, etc.) have been discovered. Among the many unique and attractive properties of 2D materials, mechanical properties play important roles in manufacturing, integration and performance for their potential applications. Mechanics is indispensable in the study of mechanical properties, both experimentally and theoretically. The coupling between the mechanical and other physical properties (thermal, electronic, optical) is also of great interest in exploring novel applications, where mechanics has to be combined with condensed matter physics to establish a scalable theoretical framework. Moreover, mechanical interactions between 2D materials and various substrate materials are essential for integrated device applications of 2D materials, for which the mechanics of interfaces (adhesion and friction) has to be developed for the 2D materials. Here we review recent theoretical and experimental works related to mechanics and mechanical properties of 2D materials. While graphene is the most studied 2D material to date, we expect continual growth of interest in the mechanics of other 2D materials beyond graphene.

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Section: Strength and Toughnessmentioning

confidence: 99%

A review on mechanics and mechanical properties of 2D materials—Graphene and beyond

Akinwande

Brennan

Bunch

et al. 2017

Extreme Mechanics Letters

1,048

649

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“…All simulations are performed with LAMMPS (http://lammps.sandia.gov, [8]). See [9][10][11] for more details regarding the set up of the molecular simulations.…”

Section: Simulation Methodsmentioning

confidence: 99%

Fundamentals of brittle failure at the atomic scale

Brochard

Souguir

Sab

2019

Proceedings of the 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures

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In this work, we investigate the elementary processes of brittle failure initiation with molecular simulation techniques. Failure initiation theories aim at bridging the gap between energy-driven failure at high stress concentrations and stress-driven failure in absence of stress concentration, and thus capturing the transition at moderate stress concentrations and associated scale effects. We study graphene, which is one of the few materials with a sufficiently small characteristic length (ratio between toughness and strength) to be addressed by molecular simulations. We also consider a toy model that proves helpful for physical interpretations. Performing molecular simulations of precracked graphene, we found that its failure behavior can overcome both strength and toughness in situations of very high or low stress concentrations, respectively; which is consistent with one particular theory, namely Finite Fracture Mechanics (FFM), which considers failure initiation as the nucleation of a crack over a finite length. Details of the atomic mechanisms of failure are investigated in the athermal limit (0K). In this limit, failure initiates as an instability (negative eigenvalue of the Hessian matrix), irrespective of the stress concentration. However, the atomic mechanisms of failure and their degeneracy (eigenvector of the negative eigenvalue) strongly depend on stress concentration and points to the nucleation of a deformation band whose length decreases with stress concentration. This atomic description is quite similar to FFM theory. At finite temperature, failure is no more deterministic because of thermal agitation. An extensive study to characterize the effects of temperature, loading rate and system size leads to the formulation of a universal scaling law of strength and toughness which extends existing theory (Zhurkov) to size effects. Interestingly, the scalings of stress-driven failure (strength) and of energy-driven failure (toughness) differ only regarding the scaling in size, which relates to the effect of stress concentration on degeneracy identified in the athermal limit.

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“…This non-linear behaviour may be due to factors such as: stress, energy release, non-linear deformations prior fracture and the phonon and atomic bonds instabilities. [25][26][27]…”

Section: Failure Responsementioning

confidence: 99%