Molecular-dynamics simulation-based cohesive zone representation of intergranular fracture processes in aluminum

Yamakov, V.; Saether, Erik; Phillips, Dawn R.; Glaessgen, Edward H.

doi:10.1016/j.jmps.2006.03.004

Cited by 201 publications

(134 citation statements)

References 52 publications

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“…The GB thus formed is a <1 1 0> ∑99 symmetric tilt GB. Crack propagation along this GB has been extensively studied by MD simulations [36][37][38] at a cryogenic temperature of T = 100 K.…”

Section: Example Of An Edge Crack Simulation Along a Grain Boundary Imentioning

confidence: 99%

“…In the stresses discussed in [36][37][38], it was found that, while in one direction the crack becomes blunted by deformation twinning, in the opposite direction it propagates in a brittle-like manner with very little dislocation emission. The latter direction has been chosen as the propagation direction for the edge crack of the simulation in Figure 12.…”

Section: Example Of An Edge Crack Simulation Along a Grain Boundary Imentioning

confidence: 99%

“…The latter direction has been chosen as the propagation direction for the edge crack of the simulation in Figure 12. The simulation using the ESCM approach performed at room temperature showed higher dislocation plasticity than at T = 100 K [36][37][38]. The remaining problem is how to transfer this plasticity to the FEM continuum.…”

Section: Example Of An Edge Crack Simulation Along a Grain Boundary Imentioning

confidence: 99%

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An embedded statistical method for coupling molecular dynamics and finite element analyses

Saether

Yamakov

Glaessgen

2009

Numerical Meth Engineering

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SUMMARYThe coupling of molecular dynamics (MD) simulations with finite element methods (FEM) yields computationally efficient models that link fundamental material processes at the atomistic level with continuum field responses at higher length scales. The theoretical challenge involves developing a seamless connection along an interface between two inherently different simulation frameworks. Various specialized methods have been developed to solve particular classes of problems. Many of these methods link the kinematics of individual MD atoms with FEM nodes at their common interface, necessarily requiring that the finite element mesh be refined to atomic resolution. Some of these coupling approaches also require simulations to be carried out at 0 K and restrict modeling to two-dimensional material domains due to difficulties in simulating full threedimensional material processes. In the present work, a new approach to MD-FEM coupling is developed based on a restatement of the standard boundary value problem used to define a coupled domain. The method replaces a direct linkage of individual MD atoms and finite element (FE) nodes with a statistical averaging of atomistic displacements in local atomic volumes associated with each FE node in an interface region. The FEM and MD computational systems are effectively independent and communicate only through an iterative update of their boundary conditions. With the use of statistical averages of the atomistic quantities to couple the two computational schemes, the developed approach is referred to as an embedded statistical coupling method (ESCM). ESCM provides an enhanced coupling methodology that is inherently applicable to three-dimensional domains, avoids discretization of the continuum model to atomic scale resolution, and permits finite temperature states to be applied.

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Section: Example Of An Edge Crack Simulation Along a Grain Boundary Imentioning

confidence: 99%

Section: Example Of An Edge Crack Simulation Along a Grain Boundary Imentioning

confidence: 99%

Section: Example Of An Edge Crack Simulation Along a Grain Boundary Imentioning

confidence: 99%

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An embedded statistical method for coupling molecular dynamics and finite element analyses

Saether

Yamakov

Glaessgen

2009

Numerical Meth Engineering

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“…For fracture simulations, the traction-displacement relationship (as introduced by Dugdale and Barenblatt [3,4]), is used to model the cohesive properties of the grain boundary (GB) interface for a specific fracture mode. The traction-displacement relationship in this strategy is extracted from atomistic molecular dynamics (MD) simulations [5], and is incorporated into cohesive-zone models (CZM) [6] used in finite element models [7]. This yields a finite element analysis capability to study the behavior of metallic microstructural damage at the grain scale [1,2].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, a methodology for extracting CZMs from atomistic simulations of crack propagation has been developed [5]. In this paper, the concept of implementing a statistical CZVE ensemble to extract a CZM constitutive law in terms of a traction-displacement relationship will be used in an improved coupled atomistic-continuum model for intergranular fracture in aluminum.…”

Section: Introductionmentioning

confidence: 99%

Multiscale modeling of intergranular fracture in aluminum: constitutive relation for interface debonding

2008

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Intergranular fracture is a dominant mode of failure in ultrafine grained materials. In the present study, the atomistic mechanisms of grain-boundary debonding during intergranular fracture in aluminum are modeled using a coupled molecular dynamics -finite element simulation. Using a statistical mechanics approach, a cohesive-zone law in the form of a traction-displacement constitutive relationship, characterizing the load transfer across the plane of a growing edge crack, is extracted from atomistic simulations and then recast in a form suitable for inclusion within a continuum finite element model. The cohesive-zone law derived by the presented technique is free of finite size effects and is statistically representative for describing the interfacial debonding of a grain boundary (GB) interface examined at atomic length scales. By incorporating the cohesive-zone law in cohesive-zone finite elements, the debonding of a GB interface can be simulated in a coupled continuum-atomistic model, in which a crack starts in the continuum environment, smoothly penetrates the continuum-atomistic interface, and continues its propagation in the atomistic environment. This study is a step towards relating atomistically derived decohesion laws to macroscopic predictions of fracture and constructing multiscale models for nanocrystalline and ultrafine grained materials.

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Scalable Synthesis of 2D Si Nanosheets

et al. 2017

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2D Si nanomaterials have attracted tremendous attention due to their novel properties and a wide range of potential applications from electronic devices to energy storage and conversion. However, high-quality and large-scale fabrication of 2D Si remains challenging. This study reports a room-temperature and one-step synthesis technique that leads to large-scale and low-cost production of Si nanosheets (SiNSs) with thickness ≈4 nm and lateral size of several micrometers, based on the intrinsic delithiation process of chemically leaching lithium from the Li Si alloy. Together with experimental results, a combination of theoretical modeling and atomistic simulations indicates that the formation of single SiNS arises from spontaneous delamination of nanosheets from their substrate due to delithiation-induced mismatch. Subsequently, the synthesized Si nanosheets evolve from amorphous to nanocrystalline to crystalline structures during annealing at different temperatures. It is demonstrated that these SiNSs possess unique mechanical properties, in particular ultralow friction, in contrast to their bulk counterparts.

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Molecular-dynamics simulation-based cohesive zone representation of intergranular fracture processes in aluminum

Abstract: A traction-displacement relationship that may be embedded into a cohesive zone model for microscale problems of intergranular fracture is extracted from atomistic molecular-dynamics

Cited by 201 publications

References 52 publications

An embedded statistical method for coupling molecular dynamics and finite element analyses

An embedded statistical method for coupling molecular dynamics and finite element analyses

Multiscale modeling of intergranular fracture in aluminum: constitutive relation for interface debonding

Scalable Synthesis of 2D Si Nanosheets

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