Importing Nastran Meshes

You can import a finite element model (FEM) representation from a Nastran bulk data file (.nas).

You can import a FEM representation from a file, from an external representation, or from the 3DEXPERIENCE common space. Meshes imported from a file appear as external data within the model; you can use the imported meshes for a simulation, but the finite element information is not available as it would be for a natively created mesh. Importing meshes from an external representation or the 3DEXPERIENCE common space adds the finite element information into the model, more like a natively created mesh.

All of the element types that you can create using the Mesh Creation app can be imported into the 3DEXPERIENCE platform. If elements of different dimensionality exist in the imported mesh, the 3DEXPERIENCE platform creates separate mesh parts for each type. If the imported file contains distinct sets of elements, the 3DEXPERIENCE platform creates groups. If the imported file contains solid, shell, continuum shell, membrane, or beam sections, the 3DEXPERIENCE platform creates sections.

An imported mesh is always up to date. You cannot remove an imported mesh; but you can delete it. If it is a 2D mesh, you can use the mesh editing tools to edit it.

Before you begin:
  • You must have the appropriate role to import Nastran meshes.
  • Open the Structural Model Creation or Fluid Model Creation app.
See Also
Exporting Meshes to Nastran
  1. From the top bar, click Add > Import > Import FEM.
  2. From the Source options, select one of the following:
    OptionDescription
    From file The mesh exists in a Nastran bulk data file (.bdf).
    From external representation The mesh exists in a file (.inp or .nas) that is part of the working model.
    From common space The mesh exists in a file (.inp or .nas) that is in the 3DEXPERIENCE database.
  3. Select the file from the appropriate source.
  4. Expand the Units section, and specify the units of the data you are importing.

    The selected units are converted to the units specified in your preferences for the current session. For example, if you import a model created in millimeters and the current session uses meters, all lengths are converted to meters (divided by 1000).

  5. From the Structuring option options, select one of the following:
    OptionDescription
    Dimensions Generates a mesh part per mesh dimension.

    For example, if you import a file that has mesh data for three dimensions, the 3DEXPERIENCE platform generates three mesh parts.
    Sections Generates a mesh part per property.
  6. Select Connection properties to import all connector-related objects (if present in the original model) with the FEM.

    These objects include:

    • Connectors, couplings, springs, and dashpots, along with their properties (for example, elasticity, damping, reference length, etc.)
    • Tie connections, along with their properties (for example, tie rotational degrees of freedom, constraint ratios, position tolerances, etc.)

  7. Click Import.
    A progress bar appears and displays the status of the import.

    After the import completes, the progress bar closes and the Import Report window appears.

    The import report provides diagnostics that include the status of the import, log information, and information about any unsupported Nastran cards present in the imported Nastran file. The report also displays the number of nodes, elements, and sections imported, along with any sections that were partially imported or not imported.

  8. Close the Import Report window.

The imported features appear in the tree. You can click them to view their details.