Symmetry Type
When you define shell properties for laminate layup-type shells, you can specify the layer repetition pattern. Use the drop-down list under Symmetry Type on the Shell Property Definition dialog box. You can select one of these options:
• No Symmetry—The layers are not repeated.
• Symmetrical—The layers are repeated in reverse order.
• Antisymmetrical—The layers are repeated in reverse order, and the orientation is also changed.
For example, a three-layer laminate would change as follows:
|
No Symmetry
|
a b c
|
|
Symmetrical
|
a b c c b a
|
|
Antisymmetrical
|
a b c -c -b -a
|
The dialog boxes require that you complete a table that defines the layers in your laminate. Each line in the table represents either a ply or sub-laminate of the shell property being defined. Note that the row numbers decrease as you go down the list since plies are traditionally numbered from the bottom up.