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# compute smd/tlsph/stress command¶

## Syntax¶

compute ID group-ID smd/tlsph/stress

• ID, group-ID are documented in compute command

• smd/tlsph/stress = style name of this compute command

## Examples¶

compute 1 all smd/tlsph/stress


## Description¶

Define a computation that outputs the Cauchy stress tensor for particles interacting via the Total-Lagrangian SPH pair style.

See this PDF guide to using Smooth Mach Dynamics in LAMMPS.

## Output info¶

This compute calculates a per-particle vector of vectors (tensors), which can be accessed by any command that uses per-particle values from a compute as input. See the Howto output doc page for an overview of LAMMPS output options.

The values will be given in units of pressure.

The per-particle vector has 7 entries. The first six entries correspond to the xx, yy, zz, xy, xz and yz components of the symmetric Cauchy stress tensor. The seventh entry is the second invariant of the stress tensor, i.e., the von Mises equivalent stress.

## Restrictions¶

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

This quantity will be computed only for particles which interact with the Total-Lagrangian SPH pair style.

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