Creating a Simcenter Samcef superelement from a Nastran DMIG file

You can create a Simcenter Samcef superelement from an external DMIG file in two ways, depending on whether the Use Sequential Cards Reading check box is selected.

Sequentially read DMIG

When you select Use Sequential Cards Reading , Simcenter Samcef will import the DMIG with the following limitations and rules:

• The file must contain GRID or SPOINT points definition.

• You can only import a GUYAN superelement.

• The file must contain the following data in this order: GRID/SPOINT points definition, stiffness matrix, mass matrix, and viscous damping matrix.

Standard DMIG

When you clear the Use Sequential Cards Reading check box, Simcenter Samcef will import the DMIG with the following limitations and rules:

• SPOINT must appear after GRID points.

• You must add the following lines in the original BDF file to specify the kind of matrix each DMIG is related to:If DMIG name is related to Stiffness (this is defined in NASTRAN by the line K2GG=NAME in the Case Control Section):$NASSAM_K2GG NAMENote: NAME is the name that appears on the DMIG cards.If DMIG name is related to Mass (this is defined in NASTRAN by the line M2GG=NAME in the Case Control Section):$NASSAM_M2GG NAMEIf DMIG name is related to Viscous Damping (this is defined in NASTRAN by the line B2GG=NAME in the Case Control Section):$NASSAM_B2GG NAME

Note:

This the default and recommended method.

Using this method, you can also import CRAIG-BAMPTON (CMS) superelements.

For more details, see the conversion of Nastran DMIG files in the Simcenter Samcef solver documentation.

Where do I find it?

Application	Pre/Post
Prerequisite	A Simulation file as the work part and displayed partSimcenter Samcef as the specified solver.Structural as the specified analysis type.Superelement Creation as the specified solution type.Convert Superelement form Other Solver as the specified Superelement Type.
Location in dialog box	General page → Nastran DMIG as the External Superelement Type.

Look up more details

Solution dialog box (Simcenter Samcef Superelement Creation Analysis)

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Creating a Simcenter Samcef superelement from a Nastran DMIG file, Simcenter 3D 2021.1 Series

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