VOLT
Plugins

Atomic Strain

Compute per-atom strain tensors from atomic configurations.

Overview

Atomic Strain computes per-atom strain tensors from atomic configurations. It calculates Green-Lagrangian strain, von Mises strain, and principal strains for deformation analysis in atomistic simulations.

Parameters

ParameterTypeDefaultDescription
cutofffloat3.0Cutoff radius for neighbor search.
referencefileReference LAMMPS dump file. If omitted, the current frame is used (≈ zero strain).
eliminateCellDeformationboolfalseEliminate cell deformation.
assumeUnwrappedboolfalseAssume unwrapped coordinates.
calcDeformationGradientbooltrueCompute deformation gradient F.
calcStrainTensorsbooltrueCompute strain tensors.
calcD2minbooltrueCompute D²min (nonaffine displacement).

Output

{outputBase}_atomic_strain.msgpack

// Voigt order: [xx, yy, zz, xy, xz, yz]
type StrainTensor = [float, float, float, float, float, float];

// Row-major 3×3: [xx, yx, zx, xy, yy, zy, xz, yz, zz]
type DeformationGradient = [float, float, float, float, float, float, float, float, float];

interface PerAtomProperties {
    id: int;
    shear_strain: float;
    volumetric_strain: float;
    // when calcStrainTensors = true
    strain_tensor?: StrainTensor;
    // when calcDeformationGradient = true
    deformation_gradient?: DeformationGradient;
    // null when calcD2min = false
    D2min: float | null;
    invalid: boolean;
}

interface AtomicStrainOutput {
    main_listing: {
        cutoff: float;
        num_invalid_particles: int;
        average_shear_strain: float;
        average_volumetric_strain: float;
        max_shear_strain: float;
    };
    "per-atom-properties": PerAtomProperties[];
}

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