The effect of time step, thermostat, and strain rate on ReaxFF simulations of mechanical failure in diamond, graphene, and carbon nanotube
Document Type
Article
Publication Date
8-5-2015
Department
Department of Mechanical Engineering-Engineering Mechanics
Abstract
As the sophistication of reactive force fields for molecular modeling continues to increase, their use and applicability has also expanded, sometimes beyond the scope of their original development. Reax Force Field (ReaxFF), for example, was originally developed to model chemical reactions, but is a promising candidate for modeling fracture because of its ability to treat covalent bond cleavage. Performing reliable simulations of a complex process like fracture, however, requires an understanding of the effects that various modeling parameters have on the behavior of the system. This work assesses the effects of time step size, thermostat algorithm and coupling coefficient, and strain rate on the fracture behavior of three carbon-based materials: graphene, diamond, and a carbon nanotube. It is determined that the simulated stress-strain behavior is relatively independent of the thermostat algorithm, so long as coupling coefficients are kept above a certain threshold. Likewise, the stress-strain response of the materials was also independent of the strain rate, if it is kept below a maximum strain rate. Finally, the mechanical properties of the materials predicted by the Chenoweth C/H/O parameterization for ReaxFF are compared with literature values. Some deficiencies in the Chenoweth C/H/O parameterization for predicting mechanical properties of carbon materials are observed.
Publication Title
Journal of Computational Chemistry
Recommended Citation
Jensen, B.,
Wise, K.,
&
Odegard, G. M.
(2015).
The effect of time step, thermostat, and strain rate on ReaxFF simulations of mechanical failure in diamond, graphene, and carbon nanotube.
Journal of Computational Chemistry,
36(21), 1587-1596.
http://doi.org/10.1002/jcc.23970
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/3700
Publisher's Statement
© 2015 Wiley Periodicals, Inc. Publisher’s version of record: https://doi.org/10.1002/jcc.23970