Define and Assign the Element Coordinate Systems

Two local coordinate systems will be created to orient the composite plies.

1. To define a local, rectangular coordinate system with the longitudinal axis of the ply material aligned with the global x-axis, enter the following into the command prompt: LOCAL, 11, 0, 0, 0, 0, 0, 90, 0. This coordinate system will be used for the 0° plies.
2. To define a local, rectangular coordinate system with the longitudinal axis of the ply material aligned orthogonally with the global x-axis, enter the following into the command prompt: LOCAL, 12, 0, 0, 0, 0, 0, 90, 90. This coordinate system will be used for the 90° plies.
3. Now we can assign the coordinate systems to the components created previously to properly align the ply layers. Type the following commands into the command prompt.
   • EMODIF, bottom_0, ESYS, 11
   • EMODIF, middle_0, ESYS, 11
   • EMODIF, top_0, ESYS, 11
   • EMODIF, bottom_90, ESYS, 12
   • EMODIF, top_90, ESYS, 12

Refer to the ANSYS APDL documentation for additional details on the LOCAL and EMODIF commands.