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# compute plasticity/atom command¶

## Syntax¶

compute ID group-ID plasticity/atom

• ID, group-ID are documented in compute command

• plasticity/atom = style name of this compute command

## Examples¶

compute 1 all plasticity/atom


## Description¶

Define a computation that calculates the per-atom plasticity for each atom in a group. This is a quantity relevant for Peridynamics models. See this document for an overview of LAMMPS commands for Peridynamics modeling.

The plasticity for a Peridynamic particle is the so-called consistency parameter ($$\lambda$$). For elastic deformation, $$\lambda = 0$$, otherwise $$\lambda > 0$$ for plastic deformation. For details, see (Mitchell) and the PDF doc included in the LAMMPS distribution in doc/PDF/PDLammps_EPS.pdf.

This command can be invoked for one of the Peridynamic pair styles: peri/eps.

The plasticity value will be 0.0 for atoms 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 page for an overview of LAMMPS output options.

The per-atom vector values are unitless numbers $$\lambda \ge 0.0$$.

## Restrictions¶

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

## Default¶

none

(Mitchell) Mitchell, “A non-local, ordinary-state-based viscoelasticity model for peridynamics”, Sandia National Lab Report, 8064:1-28 (2011).