IV.1.6 Organization of FEM in files and directories

One gives here information on the way the model has been split into several files and the organization of the files into different directories.

The files are located in six different directories:

• The directory “MAINS” contains the main data files that are used for Nastran calculations. The “main” files define various execution parameters, the load cases,... They also include model files located in other directories. The main files have a “.bdf” extension.
• All files defining materials (“MAT*” cards) are located in “MATS” directory. All these files have a “.bdf” extension.
• All files defining property cards are defined in “PROPS” directory. All these files have a “.bdf” extension.
• In directory “FIXAS”, one places the files that define fixations of the structure. All these files have a “.bdf” extension.
• In directory “LOADS” are the files that define loads applied to the structure. These loads may include local forces, quasi-static loads, temperature fields for thermo-elastic calculations,...
• In directory “MESH” are located all the elements defining the structure, its internal connections, its GRIDS, its coordinate systems,... This is normally the largest directory. Note that one makes the distinction between the internal connections modeled with RBE2 elements, and their CBAR version for thermo-elastic calculations.
• In directory “EXEC_OP2”, the main bdf files should be copied. (Actually, they already have been copied in the directory.) This is the directory in which the Nastran runs should be done. Otherwise, it is also possible to make the calculations elsewhere. But then, the examples should be modified, or symbolic links will have to be created.
• In directory “EXEC_XDB”, one finds the same bdf files as in “EXEC_OP2” directory except that in each file the line “PARAM POST -1” as been replace by “PARAM POST 0”. This ensures that an xdb Result file shall be produced instead of an op2. The remarks done for directory “EXEC_OP2” apply to directory “EXEC_XDB”.

Note also that each file include in a “.bdf” main data file can itself include other files.

The directory “PATRAN” contains a Patran session file that can be used to import the definition of groups in a Patran or FeResPost DataBase.