Prev Subsection 3.14.3: The Prestrain Update Rules Up Subsection 3.14.3: The Prestrain Update Rules Subsubsection 3.14.3.2: prestrain update rule Next
3.14.3.1 Using Update rules
In order to apply an update rule, a constraint definition must be added to the Constraints section of the input file. The type attribute is used to specify which update rule to use.
<Constraints>
<constraint type="[name of update rule]">
<!-- parameters go here -->
</constraint>
</Constraints>
The following table lists the available update rules.
| type | description |
| prestrain | Eliminate distortion due to incompatibility |
| in-situ stretch | Enforce the given in-situ fiber stretches |
Below, the supported update rules are presented in more detail. All of them share parameters for controlling the convergence of the update algorithm and these shared parameters are listed in the following table.
| parameter | description | initial value |
| update | update flag (1) | 1 |
| tolerance | convergence tolerance | 0.0 |
| min_iters | minimum number of iterations | 0 |
| max_iters | maximum number of iterations | -1 (i.e. ignored) |
Comments:
- By specifying a loadcurve for the update flag, the update can be delayed. This can be useful if, for instance, the prestrain is applied incrementally and the update rule should not be applied until the full prestrain field is applied. In that case, specifying a loadcurve for the update flag that is zero while the prestrain is applied, will delay the update process.