Importing Nastran data

You can use the Import Simulation dialog box to import Nastran:

• ASCII format files (.dat, .bdf, .pch)

• Binary format files (.op2)

You can use the options in the Import Simulation dialog box to control which data the software imports as well as how the software imports that data.

For a list of the Nastran syntax that is currently supported for import, see Nastran import and export support.

Selecting a performance mode

Use the Mode option to control how the software imports the data in your input file.

• Select Performance to have the software import the data using a predefined set of import options that reduce the overall import time. For example, with the Performance option, the software imports all data in the bulk data and non-bulk data sections of your input file with minimal data checking. Use this option when you want to maximize the import performance for very large models.

• Select General if you want to individually select the different import options. For example, with the General option, you can select which sections of bulk and non-bulk data to import. You can also use the Data checking option to have Pre/Post validate the existence of each node on a given element in your input file. Use this option when you want to granularly control how the software imports the data, or when you are not concerned about the time required to import the data.

Specifying the analysis type

You can use the Analysis Type list to either specify the type of analysis contained in the file to import, or you can select auto-detect to have the software automatically determine the analysis type. Pre/Post uses this analysis type to set the analysis type for the FEM and Simulation files that it creates during the import process.

• If you specify an analysis type that is not compatible with the specified solver or with the solution type contained in the input file, the software automatically determines the analysis type and prints a message to the Information window.

• If the solver input file contains case control commands or bulk data entries that are not supported by the specified analysis type, the software prints a message to the Information window that lists the unsupported syntax.

Note:

The Analysis Type option is not available if you use the Append command to import the input file.

Selectively importing data

When you import a Nastran input file, you can use the Selective Import options to control which bulk data entries that the software imports. You can choose to selectively import the entries either by theirBy card name or By card family (such as loads, boundary conditions, or DOFs).

If you choose the By card name option, you can also choose to import selected entries as either commented or uncommented User Defined Text. Importing selected bulk data entries as uncommented User Defined Text can be helpful if you need to import an entry that is only partially supported for import (not all fields are supported). If you import the entry as uncommented User Defined Text, the software imports all fields.

Note:

When you use the Selective Import capability, do not to make modifications to the unsupported commands or bulk data entries. If you make changes to unsupported syntax, Nastran may either fail to solve the file with a FATAL error message or generate incorrect results.

Importing auxiliary files

When you import an ASCII input file, you can use the Auxiliary File Import option to import a second ASCII format file. The software includes the auxiliary input file with the primary input file. For example, if you have a group of parameters that you typically use for all analyses, you could save those parameters in a separate file. You could then use the Auxiliary File Import option to include that parameter file each time you import a .dat file.

If your Nastran input file contains syntax that is not supported, you can use the Import unsupported cards option to control whether the software imports that syntax as a commented or uncommented User Defined Text modeling object.

For example, you can use this option if your model contains an element, such as the RTRPLT bulk data entry, that is not supported. If you import the element as an uncommented User Defined Text modeling object and then solve, Nastran should solve the file and produce correct results.

Note:

When you use the Import unsupported cards capability, do not to make modifications to the unsupported commands or bulk data entries. If you make changes to unsupported syntax, Nastran may either fail to solve the file with a FATAL error message or generate incorrect results.

Where do I find it?

Application	Pre/Post
Menu	File→Import→Simulation

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

Browse Simcenter 3D help by product area

Importing Nastran data, Simcenter 3D 2021.1 Series

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