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*CONTROLS

Keyword type: step

This option is used to change the iteration control parameters. It should only be used by those users who know what they are doing and are expert in the field. There are two, mutually exclusive parameter: PARAMETERS and RESET. The RESET parameter resets the control parameters to their defaults. With the parameter PARAMETERS is used to change the defaults. It can take the value TIME INCREMENTATION, FIELD or LINE SEARCH. If the TIME INCREMENTATION value is selected, the number of iterations before certain actions are taken (e.g. the number of divergent iterations before the increment is reattempted) can be changed and effect of these actions (e.g. the increment size is divided by two). The FIELD parameter can be used to change the convergence criteria themselves.

Finally, LINE SEARCH can be used to change the line search parameters (only for face-to-face penalty contact). The line search parameter scales the correction to the solution calculated by the Newton-Raphson algorithm such that the residual force is orthogonal to the correction. This requires the solution of a nonlinear equation, and consequently an iterative procedure. In CalculiX this procedure is approximated by a linear connection between:

For details of the line seach algorithm the reader is referred to [78].

First line:

There are no subsequent lines if the parameter RESET is selected.

Following lines if PARAMETERS=TIME INCREMENTATION is selected:

Second line:

Third line:

Following lines if PARAMETERS=FIELD is selected:

Second line:

Following lines if PARAMETERS=LINE SEARCH is selected:

Second line:

Example:

*CONTROLS,PARAMETERS=FIELD
1.e30,1.e30,0.01,,0.02,1.e-5,1.e-3,1.e-8

leads to convergence in just one iteration since nearly any residuals are accepted for convergence ( $ R^{\alpha}_n=10^{30}$ and $ C^{\alpha}_n=10^{30}$.


Example files: beammrco.


next up previous contents
Next: *COUPLED TEMPERATURE-DISPLACEMENT Up: Input deck format Previous: *CONTACT PRINT   Contents
guido dhondt 2016-03-08