\(\renewcommand{\AA}{\text{Å}}\)

compute bpm/peri/damage/atom command

Syntax

compute ID group-ID bpm/peri/damage/atom

  • ID, group-ID are documented in compute command

  • bpm/peri/damage/atom = style name of this compute command

Examples

compute 1 all bpm/peri/damage/atom

Description

Added in version TBD.

Define a computation that calculates the volume-weighted bond damage of each peridynamic node for the bond_style bpm/peri model. The damage of node i is

\[d_i = 1 - \frac{\sum_{j\,\mathrm{(intact)}} V_j}{\sum_{j\,\mathrm{(initial)}} V_j}\]

where the numerator sums the nodal volumes \(V_j\) of the bonds that are still intact and the denominator is the reference interaction volume (the same sum over all bonds present in the initial configuration). Damage is 0 for a fully intact node and approaches 1 as a node loses bonds, so it is a convenient measure for visualizing cracks and fracture surfaces. It is the BPM-framework equivalent of the legacy compute damage/atom.

The reference interaction volume is recorded by bond_style bpm/peri when the bonds are first set up, so that compute style must be defined for this compute to be used. Damage is 0 for nodes not in the specified compute group.

Output info

This compute calculates a per-atom vector, which can be accessed by any command that uses per-atom values from a compute as input. See the Howto output doc page for an overview of LAMMPS output options. The per-atom values are unitless, between 0 and 1.

Restrictions

This compute is part of the BPM package. It is only enabled if LAMMPS was built with that package. See the Build package page for more info.

This compute requires bond_style bpm/peri, which supplies the reference interaction volume, and a per-atom vfrac property.

Default

none