An atomistic study of fracture

Chang, Ray-I

doi:10.1007/bf00189819

Cited by 41 publications

(16 citation statements)

References 18 publications

(19 reference statements)

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“…17 The first atomistic simulations of crack propagation were carried out in the early 1970s using model systems representing bcc and fcc metals, and diamondlike materials. [18][19][20] More recently, largescale atomistic simulations of crack propagation in more complicated systems and microstructures have been carried out. These have included, for example, a bicrystal, 21 nanocrystalline solids, 22 notched graphene, 23 and other more complicated networks of grains and grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

Atomistic modeling of the fracture of polycrystalline diamond

et al. 2000

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A series of molecular-dynamics simulations using a many-body interatomic potential has been performed to investigate the behavior under load of several ͗001͘ and ͗011͘ symmetrical tilt grain boundaries ͑GB's͒ in diamond. Cohesive energies, the work for fracture, maximum stresses and strains, and toughness as a function of GB type are evaluated. Results indicate that special short-period GB's possess higher strengths and greater resistance to crack propagation than GB's in nearby misorientation angles. Based on dynamic simulations, it was found that the mechanism of interface failure for GB's without preexisting flaws is not that implied by Orovan's criterion, but rather GB strength is defined by GB type instead of cleavage energy. In simulations of crack propagation within GB's on the other hand, it was found that critical stresses for crack propagation from atomistic simulation and from the Griffith criterion are consistent, indicating that GB cleavage energy is an important characteristic of GB toughness. Crack propagation in polycrystalline diamond samples under an applied load was also simulated and found to be predominantly transgranular rather than intergranular.

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Section: Introductionmentioning

confidence: 99%

Atomistic modeling of the fracture of polycrystalline diamond

et al. 2000

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“…MD was first applied to the fracture problem by crack propagation because the fracture of a material occurs at the atomic level and MD is a powerful tool for simulating the microseale behavior of atoms [5,6]. Another principal factor causing a fracture in a material is the grain boundary (GB), which is considered as a non-homogeneous phase where dislocations or impurities are accumulated.…”

Section: Introductionmentioning

confidence: 99%

Microscopic study for the behavior of grain boundary using molecular dynamics

Kim

Choi

2000

Metals and Materials

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In this study, MD simulations have been performed to observe the behavior of a grain boundary in an aFe plate under 2-dimensional loading. In MD simulation, the acceleration of every molecule can be achieved from the potential energy and the force interacting between each molecule, and the integration of the motion equation by using the Verlet method gives the displacement of each molecule. Initially, four ot-Fe rectangular plates which have different misorientation angles of grain boundary were modeled by using the Johnson potential and Morse potential. We compared the potential energy of the grain boundary system with that of the perfect structure model, which does not have a grain boundary inside. Also, we could obtain the width of the grain boundary by investigating the local potential energy distribution. The tensile loading for each grain boundary model at room temperature was applied and the behavior of the grain boundary was studied. From this study it was clarified that when the Johnson potential is used, the obvious fracture mechanism occurs along the grain boundary. With the Morse potential, the diffusion of the grain boundary appears instead of the grain boundary fracture.

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“…Early models used to study atomistic processes in the vicinity of crack tips or dislocation cores relied heavily on continuum elasticity theory, without including atoms in the far-field. Early work featured one-way [9][10][11][12][13][14] or two-way [15][16][17][18][19] coupled methods, in which displacement fields established at the interface between continuum and atomistic regions were computed either from sophisticated interfacial conditions or from initial conditions derived from continuum elasticity theory. Increases in computing power permitted more realistic two-way couplings, whereby atomistic fields were permitted to affect the far-field elastic continua through the latter's discretization with finite elements [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Multiscale Modeling of Point and Line Defects in Cubic Lattices

Chung

Clayton

2007

Int J Mult Comp Eng

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) March 2008 REPORT TYPE Reprint DATES COVERED (From SPONSOR/MONITOR'S ACRONYM(S) 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTESA reprint from the International Journal for Multiscale Computational Engineering, vol. 5, nos. 3 and 4, pp. 203-226, 2007. 14. ABSTRACT A multilength scale method based on asymptotic expansion homogenization (AEH) is developed to compute minimum energy configurations of ensembles of atoms at the fine length scale and the corresponding mechanical response of the material at the coarse length scale. This multiscale theory explicitly captures heterogeneity in microscopic atomic motion in crystalline materials, attributed, for example, to the presence of various point and line lattice defects. The formulation accounts for large deformations of nominally hyperelastic, monocrystalline solids. Unit cell calculations are performed to determine minimum energy configurations of ensembles of atoms of body-centered cubic tungsten in the presence of periodic arrays of vacancies and screw dislocations of line orientations [111] or [100]. Results of the theory and numerical implementation are verified versus molecular statics calculations based on conjugate gradient minimization (CGM) and are also compared with predictions from the local Cauchy-Born rule. For vacancy defects, the AEH method predicts the lowest system energy among the three methods, while computed energies are comparable between AEH and CGM for screw dislocations. Computed strain energies and defect energies (e.g., energies arising from local internal stresses and strains near defects) are used to construct and evaluate continuum energy functions for defective crystals parameterized via the vacancy density, the dislocation density tensor, and the generally incompatible lattice deformation gradient. For crystals with vacancies, a defect energy increasing linearly with vacancy density and applied elastic deformation is suggested, while for crystals with screw d...

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An atomistic study of fracture

Cited by 41 publications

References 18 publications

Atomistic modeling of the fracture of polycrystalline diamond

Atomistic modeling of the fracture of polycrystalline diamond

Microscopic study for the behavior of grain boundary using molecular dynamics

Multiscale Modeling of Point and Line Defects in Cubic Lattices

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