The mesh stack orientation is important when meshing parts with continuum shell, cohesive, cylindrical, or gasket elements because these elements have a distinctive directional behavior. If you use sweep meshing, the default stack orientation follows the direction of the sweep path, and you may be able to change the stack orientation by picking a different sweep path. However, you must assign a sweep direction to each cell in a part separately—a time-consuming process—and the available sweep directions may not include your desired stack direction.
The stack orientation tool allows you to assign a stack orientation to all cells or to selected cells within a solid part or part instance, as long as the cells do not have tetrahedral elements assigned. You can use the tool to apply a stack orientation quickly to a group of cells in a single operation. You assign the stack orientation based on a selected face; the stack is oriented such that the selected face is the top of the stack. Abaqus/CAE applies the orientation regardless of the mesh technique used for the cells; so the sweep direction, if one exists, does not matter.
The stack orientation tool was used to assign an orientation through the thickness of the part in Figure 17–139, as shown by the red arrow; the top faces of the elements are colored brown. The complex profile of the swept solid part did not allow the desired stack orientation using the sweep path—the two available sweep directions are indicated by the black arrow in the figure.
Application of a new stack orientation may vary depending on the cells selected. Figure 17–140 illustrates a case where the stack direction changes as more cells are meshed. The upper left face was used for the reference orientation, so the mesh orientations for the two disconnected cells in the center image match this orientation. However, when the center cell is meshed, the orientation of the elements in the lower right cell is updated to align with the other two cells, as shown in the image on the right.
To apply a mesh stack direction:
From the main menu bar, select Mesh
OrientationStack.
Abaqus/CAE displays prompts in the prompt area to guide you through the procedure.
Tip:
You can also set a mesh stack direction using the 
tool, located in the Mesh module toolbox (for more information, see “Using the Mesh module toolbox,” Section 17.15.), and the Assign stack direction button, located in the Mesh Controls dialog box.
If your part contains multiple cells, select the cells for which you want to assign a stack direction.
Select a top face to define the reference orientation.
Abaqus/CAE prompts you to confirm your selections before assigning the orientation.
Click Yes to accept the selected face and corresponding orientation, or click No to return to Step 3.
When you accept the reference face, Abaqus/CAE applies the stack direction to the selected cells.
If any of the selected cells contains cylindrical elements, Abaqus/CAE displays a warning message indicating that the cylindrical elements must be deleted to apply a new stack direction. Click Yes to delete the cylindrical mesh or No to cancel the stack direction procedure.
