16.2.1. Defining a Section and Associating a Section ID Number
Use the SECTYPE command to define a section and associate it with a section ID number. For example,
the following command assigns a section identification number (2) to a shell section:
Command(s):SECTYPE, 2, SHELL
GUI: Main Menu> Preprocessor> Sections> Shell> Add/Edit
16.2.2. Defining Layer Data
Use the SECDATA command to define the layers of a shell section. Each consecutive SECDATA command
defines the next layer's thickness, material, orientation, and number of integration points. ( The number
of integration points input on SECDATA is not used by thermal shell elements.) The layer orientation
angle is the angle between the layer coordinate system and the x-axis of the element coordinate system.
You may designate the number of integration points (1, 3, 5, 7, or 9) located thru the thickness of each
layer. When only 1, the point is always located midway between the top and bottom surfaces. If 3 or
more points, 2 points are located on the top and bottom surfaces respectively and the remaining points
are distributed equal distance between the 2 points. An exception occurs when designating 5 points,
where the quarter point locations are moved 5 percent toward their nearest layer surface to agree with
the locations selected with real constant input.The default for each layer is 3.
If a shell section has only one layer, and the number of section integration points is equal to one, then
the shell does not have any bending stiffness. This may result in solver difficulties, and may affect con-
vergence adversely.
Command(s):SECDATA, 0.5, 1, 45, 3 SECDATA, 0.5, 2, -45, 3 SECDATA, 0.5, 1, 45, 3
GUI: Main Menu> Preprocessor> Sections> Shell> Add/Edit
16.2.3. Overriding Program Calculated Section Properties
Use the SECCONTROL command to override the program calculated section properties. By default, the
program calculates shear correction factors and mass for each element based on the input section
geometry and material properties. Any values input on the SECCONTROL command will replace the
defaults. (SECCONTROL does not apply to thermal shell elements.)
Command(s):SECCONTROL, 0.8, 0.0, 0.8, 1.0
GUI: Main Menu> Preprocessor> Sections> Shell> Add/Edit
16.2.4. Specifying a Shell Thickness Variation (Tapered Shells)
Use the SECFUNCTION command to associate a tabular thickness variation with the section. A table
that describes thickness with respect to the global Cartesian coordinate system may be associated with
a shell section. This thickness is interpreted as the total thickness of a shell.The total thickness of a
layered shell, and all layer thickness values, will be scaled according to the tabular function.
Command(s):SECFUNCTION, %table_name%
GUI: Main Menu> Preprocessor> Sections> Shell> Add/Edit
16.2.5. Setting the Section Attribute Pointer
Use the SECNUM command to associate an element with a particular section. Any element created
after the SECNUM command will have this section identification number (2) as its section attribute.
Command(s):SECNUM, 2
GUI: Main Menu> Preprocessor> Meshing> Mesh Attributes> Define> Default Attribs
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