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How to Use the Nastran Data

There are four operations possible with Nastran file.

Open Nastran-format mesh file
Open the Nastran-format mesh file and generate the meshes

Save Nastran-format meshes
Model, attribute setting, and meshes created by Femtet are saved in the Nastran format

Save Nastran-format heat distribution
Model, attribute setting, meshes, and heat distribution created by Femtet are saved in the Nastran format.

Create model data from Nastran-format mesh data
Femtet-format model data is created from the Nastran-format mesh.

The details are explained in the table below.

Item

Notes

Open Nastran-format file

General

Read the Nastran-format data and create meshes.

(File extensions are .bdf, .nas, and .dat)

Supported analysis conditions

Analysis space: 3D and 2D. (The axisymmetric analysis is not supported.)
Unit: m and mm (μm is not supported.)

Supported solvers

Electric analysis
Magnetic-transient analysis [Luvens]
Stress analysis
Piezoelectric analysis
Acoustic analysis

* Depending on the analysis condition and boundary condition, there may be a case where the solvers above are not applicable.

Supported elements

3D: Tetrahedron, Quadrangular pyramid, Triangular prism, Hexahedron
2D: Triangle, Rectangle

1st-order and 2nd-order elements are available for the above.

Details

See [Analysis with Meshes in the Nastran Format] for more information.

Save Nastran-format meshes

General

The mesh data is saved in the Nastran file (.nas).

The data can be utilized by other analysis software.

Details

See [Save Meshes in the Nastran Format] for more information.

Procedure

On the [Tool] tab,

click [Save Nastran Data]

The following options are available.

[Specify a value for the body property ID]

Normally, ID numbers for the bodies such as PSOLID and PSHELL are set automatically. Any numbers can be specified as well.

[Convert to XY plane for output]

XZ plane is used for 2D analysis in Femtet. The coordinates of nodes are transformed to the XY plane.

* Available for the 2D analysis only.

[Output stator and rotor in separate files]

The data of nodes and elements of stator and rotor are output to the separate files.

The numbers for nodes and elements are assigned starting from 1 respectively.

[_Stator] and [_Rotor] will be attached to the end of the specified file names.

*This function is available for the magnetic transient analysis only.

The deformed meshes resulting from stress analysis or piezoelectric analysis can be saved as well.

The message [Do you want to apply the displacement result to each node?] will appear. Select "Yes".

Multiple number of modes and resulting deformations can be saved.

Save Nastran Heat Distribution

General

Saves the mesh and heat information in a Nastran-format file (.bdf).

The data can be utilized by other analysis software.

Details

The mesh data contains the following.

Node numbers and material numbers of tetrahedrons.
Node numbers and coordinates
Heat density of elements [W/m3]

The dimensional unit is [m].

You might need to redefine the material properties when it is used by other analysis software.

Procedure

Go to [Tool] tab

select [Save Nastran Data with Heat]

This command is disabled for the analyses which don't generate heat distribution results.

Create model data from mesh data

General

By using the Nastran-format mesh file (.bdf, .nas, and .dat),

Femtet-format model data can be created for analysis.

The analysis settings can be applied to the created model.

Details

For details, please refer to [Q14. I Want to Create a Model from Mesh Data].

Read Nastran-format result (.op2)

General

Read the Nastran-format result file (op2) to show in Femtet.

How to read

Go to and click the [File] tab , and select [Results Only] on the drop-down list.

Select Output File(*.op2) as a file type and select the file to show.

Details

See [Read Nastran-Format Result (.op2)] for the details.

- Nastran is a registered trademark of NASA.