**process strain_measure

Description

This post-processing computes the strain measures (small strain, Green, Hencky (logarithmic), the deformation gradient, Biot strain )

Syntax

**process strain_measure \(~\,\) *measure measure \(~\,\) *strain_prefix prefix [ *rotate_back ] [ *disp_prefix prefix ]

*measure measure

is the strain measure.

measure	Description
eng	The engineering strain \(\dfrac12 (\ten F + \ten F^T) -\ten 1\)
log	the logarithmic strain \(\ln \ten U\), where \(\ten F = \ten R\ten U\)
def	the deformation gradient \(\ten F\)
biot	The Biot strain tensor \(\ten U - \ten 1\)
green	Green-Lagrange strain measure \(\ten E = \dfrac12 (\ten F\ten F^T-\ten 1)\)
sd	infinitesimal strain tensor \(\ten \varepsilon = \dfrac{1}{2} \left(\nabla \vect u + \nabla^T \vect u \right)\)

*strain_prefix prefix

is the name assigned to the strain. By default, prefix = F (if measure = def_grad) and prefix = ETO for other strain measures.

*rotate_back

a flag to rotate the strain tensor back to the global frame \(\ten R \ten \square \ten R^T\).

*disp_prefix prefix

is the displacement prefix. By default U.

Example

****post_processing
 ***global_post_processing
  **file node
  **nset ALL_NODE
  **process strain_measure
   *strain_prefix E
   *measure green
****return