\(\renewcommand{\AA}{\text{Å}}\)

fix_modify AtC fields command

Syntax

fix_modify <AtC fixID> fields <all|none>
fix_modify <AtC fixID> fields <add|delete> <list_of_fields>

  • AtC fixID = ID of fix atc instance

  • fields = name of the AtC sub-command

  • all or none = output all or no fields

  • add or delete = add or delete the listed output fields

  • list_of_fields = one or more of the fields listed below:

    • density : mass per unit volume

    • displacement : displacement vector

    • momentum : momentum per unit volume

    • velocity : defined by momentum divided by density

    • projected_velocity : simple kernel estimation of atomic velocities

    • temperature : temperature derived from the relative atomic kinetic energy

    • kinetic_temperature : temperature derived from the full kinetic energy

    • number_density : simple kernel estimation of number of atoms per unit volume

    • stress : Cauchy stress tensor for eulerian analysis (atom_element_map), or first Piola-Kirchhoff stress tensor for lagrangian analysis

    • transformed_stress : first Piola-Kirchhoff stress tensor for eulerian analysis (atom_element_map), or Cauchy stress tensor for lagrangian analysis

    • heat_flux : spatial heat flux vector for eulerian, or referential heat flux vector for lagrangian

    • potential_energy : potential energy per unit volume

    • kinetic_energy : kinetic energy per unit volume

    • thermal_energy : thermal energy (kinetic energy - continuum kinetic energy) per unit volume

    • internal_energy : total internal energy (potential + thermal) per unit volume

    • energy : total energy (potential + kinetic) per unit volume

    • number_density : number of atoms per unit volume

    • eshelby_stress : configurational stress (energy-momentum) tensor defined by [Eshelby]

    • vacancy_concentration : volume fraction of vacancy content

    • type_concentration : volume fraction of a specific atom type

Examples

fix_modify AtC fields add velocity temperature

Description

Allows modification of the fields calculated and output by the AtC transfer class. The commands are cumulative, e.g.:

fix_modify AtC fields none
fix_modify AtC fields add velocity temperature

will only output the velocity and temperature fields.

Restrictions

Must be used with fix atc hardy. Currently, the stress and heat flux formulas are only correct for central force potentials, e.g. Lennard-Jones and EAM but not Stillinger-Weber.

Default

By default, no fields are output.

References

[Eshelby]

J.D. Eshelby, Philos. Trans. Royal Soc. London A, Math. Phys. Sci., Vol. 244, No. 877 (1951) pp. 87-112; J. Elasticity, Vol. 5, Nos. 3-4 (1975) pp. 321-335]