Hyperdynamics accelerated concurrent atomistic-continuum model for developing crack propagation models in elastic crystalline materials

Chakraborty, S.; Ghosh, Somnath

doi:10.1016/j.commatsci.2018.07.064

Cited by 12 publications

(4 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[29] They have been shown to be applicable to a great variety of problems. [37][38][39][40][41][42][43][44][45] Still, there are limitations to these methods. It has been found, for example, that the construction of bias potentials is not trivial.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Exploring the Chemistry of Low‐Temperature Ignition by Pressure‐Accelerated Dynamics

et al. 2020

View full text Add to dashboard Cite

Reaction models that accurately describe the complex reaction processes of ignition are key for the development of novel engine-and fuel concepts. Since reactive molecular dynamics can be used to discover reaction networks in a largely automated fashion, this method has the potential to drastically reduce the real time effort necessary for the development of reaction models. With standard reactive molecular dynamics, the simulation of low-temperature reaction processes is hindered by the small accessible time scales of only a few nanoseconds. In this work, we propose the pressure-accelerated dynamics method to overcome the time scales obstacle through exploitation of Le Chatelier's principle. For the example of pentane low-temperature ignition, we show that with pressure-accelerated dynamics, the ReaxFF reactive force field, and the ChemTraYzer not only the known key low-temperature igniton pathways can be found, but also reactions that are not yet included in reaction models.

show abstract

Section: Introductionmentioning

confidence: 99%

“…With the existing methods, it is possible to extend feasible timescales by multiple orders of magnitude . They have been shown to be applicable to a great variety of problems . Still, there are limitations to these methods.…”

Section: Introductionmentioning

confidence: 99%

Exploring the Chemistry of Low‐Temperature Ignition by Pressure‐Accelerated Dynamics

et al. 2020

View full text Add to dashboard Cite

show abstract

“…In the simplest form, the hyperdynamics algorithm does not need any preliminary information about the system’s potential landscape. This fact explains the application of hyperdynamics to many practically important problems, for example, water-driven degradation of polyamide, low-temperature decomposition of n -heptane, crack propagation in elastic crystalline, and dissolution of organic crystals . Metadynamics implies the introduction of the additional nonphysical term into the system’s Hamiltonian that forces the system to evolve in a particular direction (for example, along the assumed reaction coordinate).…”

Section: Introductionmentioning

confidence: 99%

Molecular Hyperdynamics Coupled with the Nonorthogonal Tight-Binding Approach: Implementation and Validation

Katin¹,

Гришаков²,

Подливаев³

et al. 2020

J. Chem. Theory Comput.

View full text Add to dashboard Cite

We present the molecular hyperdynamics algorithm and its implementation to the nonorthogonal tight-binding model NTBM and the corresponding software. Due to its multiscale structure, the proposed approach provides the long time scale simulations (more than 1 s), unavailable for conventional molecular dynamics. No preliminary information about the system potential landscape is needed for the use of this technique. The optimal interatomic potential modification is automatically derived from the previous simulation steps. The average time between adjusted potential energy fluctuations provides an accurate evaluation of physical time during the hyperdynamics simulation. The main application of the presented hyperdynamics method is the study of thermal-induced defects arising in the middle-sized or relatively large atomic systems at low temperatures. To validate the presented method, we apply it to the C60 cage and its derivative C60NH2.Hyperdynamics leads to the same results as a conventional molecular dynamics, but the former possesses much higher performance and accuracy due to the wider temperature region. The coefficient of acceleration achieves 10 7 and more. Straight lines are the linear approximations of these dependencies by the Arrhenius lawwhere  is the time that is needed for the corresponding reaction, Ea is the activation energy, kB is the Boltzmann's constant, T is the temperature. Activation energies can be derived from the slopes of approximating lines. Both MD and hyperdynamics methods predict the formation of the same Stone-Wales defect imaged in Fig. 2a. We obtain the reasonably good agreement of reaction times predicted using these methods, see Fig. 2a. Corresponding activation energies are equal to 6.22 ± 0.99 and 6.44 ± 0.22 eV for MD and hyperdynamics, respectively, see Fig. 3a. They match with the previously reported corresponding energy barrier (6.48 eV 27 ). One can see the high accuracy of hyperdynamics associated with the wide available temperature range. Note, that hyperdynamics provides reaction times of 1 s and more, whereas the comparable number of MD steps can provide only tens of nanoseconds. So, the acceleration factor due to the use of hyperdynamics reaches 10 7 and more.During the studying of heated C60NH2 cage, we observe two possible events: the C-N bond fission ( Fig. 2b) and the formation of bridge configuration with tetra-coordinated nitrogen (Fig. 2c).The latter appears only at very high temperatures (T ≥ 1800 K). Thus, we ignored this scenario in the activation energy evaluation. Such example confirms the importance of accounting for the lowtemperature region to get the actual reaction mechanism. For the fission of the C-N bond, we obtain the activation energies of 3.66 ± 0.55 and 3.28 ± 0.21 eV for MD and hyperdynamics methods, respectively. These values are close to the previously reported binding energies between NH2 functional group and small carbon nanotubes (2.5 ÷ 3.5 eV depending on the tube's chirality indices 28 ). Figure 3b demonstrates reasonably well agreement ...

show abstract

“…For the concurrent method, the regions with different scale characteristics are combined to be the whole model to balance the accuracy and efficiency. [20][21][22] The important topic in concurrent method is the connection of different scale regions. 23 A simple way is to establish the mesh transition zone to realize the variation of mesh density from mesoscopic region to macroscopic region.…”

Section: Introductionmentioning

confidence: 99%

Domain information transfer method and its application in quasi-brittle failure analysis

Sun

Gao

2019

Advances in Mechanical Engineering

View full text Add to dashboard Cite

This article presents a domain information transfer method for the purpose of quasi-brittle failure analysis. It contains two separated computational levels. On macroscopic level, the material domains are viewed as elementary substances which construct the whole structure. The macroscopic governing equations are established based on this point of view and the boundary displacements of material domains are defined as basic unknowns. Each damaged material domain will be assigned a mesoscale model and the information transfer mechanism from a mesoscale domain to a macroscale domain is established. The damage localization phenomenon is equivalently represented on macroscopic level by boundary deformation of material domains and the macroscale meshes are invariant during analysis. The information exchange element based on nonlocal quadrature scheme is proposed and the efficient upscaling is realized. The proposed method is an efficient and flexible way for quasi-brittle failure analysis.

show abstract

Hyperdynamics accelerated concurrent atomistic-continuum model for developing crack propagation models in elastic crystalline materials

Cited by 12 publications

References 28 publications

Exploring the Chemistry of Low‐Temperature Ignition by Pressure‐Accelerated Dynamics

Exploring the Chemistry of Low‐Temperature Ignition by Pressure‐Accelerated Dynamics

Molecular Hyperdynamics Coupled with the Nonorthogonal Tight-Binding Approach: Implementation and Validation

Domain information transfer method and its application in quasi-brittle failure analysis

Contact Info

Product

Resources

About