About Zones

CATIA Zones

• The surface on which the zones lie.
• A basic rosette (equivalent to a coordinates system).
  

It also contains the draping direction (by default,  the positive normal direction of the surface).
 
The zones inside a zones group include:  

• The geometry or extent of the zone, defined by an outer contour and inner contours (if any) lying on the underlying surface.
• The laminate of the zone, consisting of a smeared description of the laminate layers in the directions predefined in the Composites Parameters.  

It can reference a rosette, which overrides that of the zones group.  

When importing analysis zones into CATIA, you can create pure geometry, or add zone information as required.

Analysis Zones

The analysis zones are read from a Nastran input deck. Here, the Composites properties are defined using PCOMP (Property COMPosites) cards which are usually referenced by shell finite elements. These exist in the "Bulk Data" section of the deck. The shell elements reference the PCOMPs, which in turn reference homogeneous materials.

Example:

...
BEGIN BULK
...
$ Elements and Element Properties for region: PCOMP.
$ Composite Property Record created from P3/PATRAN composite material
$ record: PCOMP.1
$ Composite Material Description: generated by Laminate Modeler
PCOMP      1              -.66                                                                             20.             0.
                      7               .33               -45              YES               7               .33            45.               YES
                      7               .33                 0.               YES               7               .33               0.               YES 
$ Pset: "PCOMP.1" will be imported as:  "pcomp.1"
CQUAD4   1                   1                 63               347               61                2               1
CQUAD4   2                   1                 64               348               347           63               1
CQUAD4   3                   1                 65               349               348           64               1
...
$ Referenced Material Records
$ Material Record: S1454_G803
$ Description of Material:
MAT8         7                66000.         66000.      .04             4100.       5000.         5000.        1.6-9
                   1.2-5         1.2-5            20.              375.             279.        368.           268.           46.
...
$ Loads for Load Case: DEFAULT.SC1
$ Referenced Coordinate frames
CORD2R    1                                       16.3067   -3.1641539.5127   -6.1801   33.3256  39.6645
                   52.7966  19.3227        39.5127
...
ENDDATA b4420d00

The PCOMP cards contain a number of layers which reference homogeneous materials.
In this example, there are four layers of material with the ID of 7 and a thickness of 0.33.
They have an angle of -45, 45, 0 and 0 degrees with respect to the reference system of the PCOMP on the element.
Unless the SMEAR or another specialized option is defined, the input data defines the exact position of the layer.
This is necessary for calculating layered stress results.  

The PCOMP orientation is set for each element either through a coordinates system, or an angle measured from the first edge of the element.
We recommend using a coordinates system to maximize communication between design and analysis worlds.  
The stacking direction is defined by the positive normal direction of the respective element.  
The elements referencing a PCOMP card may exist in multiple independent regions: When the zones are imported into CATIA, one analysis PCOMP may correspond to many design zones.