OOF2: The Manual

Name

Nonlinear Geometric Strain (NonlinearGeometricStrain) — Rotationally invariant symmetric derivative of the displacement field.

Synopsis

NonlinearGeometricStrain()

Details

Description

The nonlinear geometric strain is the rotationally invariant form of the GeometricStrain. It is the form of the strain used by the large strain elasticity properties. Specifically,

\[
      \epsilon_{ij} = \frac12\left({\frac{\partial u_i}{\partial x_j}} + 
                    {\frac{\partial u_j}{\partial x_i}} +
                    {\frac{\partial u_k}{\partial x_i}}
                    {\frac{\partial u_k}{\partial x_j}}
                    \right)
      \] (6.151)

where \(\epsilon_{ij}\) is the strain, \(u\) is the displacement, and the repeated index k is summed.