4.14.14 NASTRAN Files

Select NASTRAN from the File Type drop-down list. Select the surface(s) for which you want to write data in the Surfaces list. If you do not select any surfaces, the entire domain is exported. You can specify which scalars you want in the Quantities list.

You have the option of selecting loads to be included in the exported file. When the Energy Equation is enabled in the Energy dialog box, you can choose the loads based on the kind of finite element analysis you intend to undertake. By selecting Structural in the Analysis list, you can select the following Structural Loads: Force, Pressure, and Temperature. By selecting Thermal in the Analysis list, you can select the following Thermal Loads: Temperature, Heat Flux, and Heat Trans Coeff. Note the following limitations with these loads:

• When the Energy Equation is disabled, only the Structural Loads options of Force and Pressure are available.

• Loads are written only on boundary walls when the entire domain is exported (i.e., if no Surfaces are selected).

Click the Write... button to save the file, using the Select File dialog box. A single file (e.g., file.bdf) is written containing coordinates, connectivity, optional loads, zone groups, and velocity. Pressure is written as PLOAD4, and heat flux is written as QHBDYE data. If you select wall zones in the Surfaces list, nodal forces are written for the walls. When data is written for the heat transfer coefficient, it is based on the wall faces rather than the nodes.

You have the option of exporting data at specified intervals during a transient calculation through the Automatic Export dialog box. See Section  4.16 for the complete details.