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/DT/NODA/Keyword3

/DT/NODA/Keyword3

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/DT/NODA/Keyword3

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Engine Keyword

/DT/NODA/Keyword3 - Nodal Time Step Control

Description

Nodal time step control.

Format

/DT/NODA/Keyword3/0

 

Or

/DT/NODA/Keyword3/1

 

grnd_ID

 

Data

Description

Keyword3

Time step control type:

STOP - The run will stop if the time step reaches and a restart file will be written.

CST - The time step becomes constant once it reaches .

The nodal mass of the node reaching is increased. Therefore, the momentum is not conserved and the mass evolution of the model should be carefully monitored along the computation.

SET - Forces are reduced in order to keep a constant time step.

Scale factor on nodal time step for the above selected option.

Default = 0.9

Minimum time step

grnd_ID

Node group identifier

Comments

1.If /DT/NODA/CST/1 is used, the group defined in grnd_ID must be a node group; then only the nodes belonging to node group, grnd_ID are affected.
2.When using /DT/NODA/CST, using a scale factor on time step, = 0.67 is recommended.
3./DT/NODA/Keyword3 is compatible with all options of /DT/Eltyp/Keyword3, (except /DT/INTER/AMS).
4./DT/NODA/CST generally applies to the whole model (or to a node group if /DT/NODA/CST/1 is used), except that it is possible to use Elementary time step for AMS (/DT/AMS) on a part group defined in Starter /AMS card and classical mass scaling (/DT/NODA/CST) at the same time: /DT/NODA/CST then applies to nodes not belonging to the AMS part group.

For example:

/DT/AMS/1

Tol_AMS

 

/DT/NODA/CST

 

This is even advised in order to minimize computing time in models where AMS only applies to selected parts. Note that it is pointless to use a higher time step in AMS than the one used in classic mass scaling since the smaller time step limits the performance.

See Also:

Nodal Time Step