prestrain gradient

Module: solid

Category: materialprop

Type string: "prestrain gradient"

Parameters

Name	Description	Default	Units
ramp	ramp	1	[]
F0	F0		[]

Description

The prestrain gradient generator defines the full prestrain gradient matrix either for the entire material or for each element separately.

This can be used to define the prestrain property of the prestrain elastic material.

The prestrain gradient that is applied is calculated by the following equation.

\[ \mathbf{F}_{g}=\mathbf{I}\left(1-r\right)+\mathbf{F}_{0}r \]

Here, \(F_{g}\) is the applied prestrain gradient, \(\mathbf{I}\) is the 3x3 identity tensor, \(\mathbf{F}_{0}\) is the target prestrain gradient, defined by F0 parameter, and \(r\) is the ramp factor.

Example:

In this example, the prestrain gradient is ramped up to a desired gradient value via a load controller.

<material id="1" type="prestrain elastic">
  <elastic type="neo-Hookean">
    <E>1.0</E>
    <v>0.3</v>
  </elastic>
  <prestrain type="prestrain gradient">
    <ramp lc="1">1.0</ramp>
    <F0>2,0,0,0,2,0,0,0,2</F0>
  </prestrain>
</material>