Assigning shell/membrane normal directions

When you create a part with shell regions or an axisymmetric part with wire regions, Abaqus assigns a direction for the normals of the regions. You can reverse the directions of the normals for these regions. In addition, you can reverse the directions for the normals of imported parts or selected orphan elements.

Related Topics
Creating and editing sections
Selecting objects within the viewport

Context:

You can also reverse the normals for skin reinforcements; however, if there are multiple skins defined on the surface of a geometric part, you cannot reverse the normal of one of those skins without reversing the normals of every skin defined for that surface. If the surface with multiple skins is a feature of a mesh part, you can reverse the normal of an individual skin without reversing the normals for the other skins defined on that surface.

When you reverse the normal direction of a region, the local normal that defines the material orientation is reversed. You can use the Query toolset to verify that the material orientation is correct for a selected region. For more information, see Using the Query toolset to obtain assignment information.

  1. If the part to which you want to assign a normal is not visible in the current viewport, click the name of the desired part in the Part list located in the context bar.

    The selected part appears in the current viewport.

  2. From the main menu bar, select AssignElement Normal.

    Tip: You can also click the tool in the Property module toolbox or select MeshOrientationNormal in the Mesh module.

    Abaqus/CAE displays the part using the shaded render style. The side of the shell where the surface normal coincides with the shell normal (top face) is colored brown; the opposite side (bottom face) is colored purple.

  3. If the selected part is geometry-based, use one of the following methods to select the regions whose normals you want to reverse:

    • Select the regions from the viewport and click mouse button 2. (For more information, see Selecting objects within the viewport.”)

      Tip: You can limit the types of objects that you can select in the viewport by using the tools in the Selection toolbar. See Using the selection options, for more information.

      If you select Skins as the object type, you can assign the section to the entire skin or to one or more of its faces. From the prompt area, select (pick entire skin) or (pick partial skin), then make your selection in the viewport. If the selected part has multiple skins, Abaqus/CAE will display the ambiguous picking options in the prompt area while you make your selection.

    • To select from a list of existing sets, do the following:

      1. Click Sets on the right side of the prompt area.

        Abaqus/CAE displays the Region Selection dialog box containing a list of available part sets.

      2. Select the part set of interest, and click Continue.

    Note:

    The default selection method is based on the selection method you most recently employed. To revert to the other method, click Select in Viewport or Sets on the right side of the prompt area.

    Abaqus/CAE reverses the shell/membrane normal directions of the selected regions.

  4. If the selected part is a mesh part, use one of the following methods to select the shell elements whose normals you want to reverse:

    Selecting individual elements:

    1. Click the arrow next to the Selection method field in the prompt area, and select Individually from the list that appears.

    2. Select an element whose normal you want to flip.

    3. ShiftClick on additional elements to add them to your selection.

    4. If necessary, CtrlClick on selected elements to unselect them.

    5. When you have finished selecting elements, click mouse button 2.

    Specifying an existing element set

    1. Click Sets on the right side of the prompt area.

      Abaqus/CAE displays the Region Selection dialog box containing a list of element sets that you have created.

    2. Select the set of elements that you want to edit, and click Continue.

    Note:

    The default selection method is based on the selection method you most recently employed. To revert to the other method, click Select in Viewport or Sets on the right side of the prompt area.

    Selecting elements using the angle method:

    1. From the field in the prompt area, select by angle.

    2. Enter an angle (from 0° to 90°), and select an element face. Abaqus/CAE selects every adjacent shell element from the selected face until the angle between the element faces is equal to or exceeds the angle that you entered. (See Using the angle and feature edge method to select multiple objects, for more information.)

    3. After you use the by angle method, you can ShiftClick on additional elements to add them to your selection or CtrlClick on selected elements to remove them from your selection. (See Combining selection techniques, for more information.)

    4. When you have finished selecting elements, click mouse button 2.

    Tip: You can limit the types of objects that you can select in the viewport by using the tools in the Selection toolbar. For more information, see Selecting objects within the viewport.”

  5. From the prompt area, select a method for reversing the shell/membrane normal:

    • Click Flip All to reverse the normal of all selected elements.

    • Click Select Normal to change the normals of the selected elements so that they point in the same direction as the normal of a reference element that you specify.

  6. If you chose Select Normal in the previous step, do the following:

    1. In the viewport, select the reference element.
    2. In the prompt area, click OK.

      Abaqus/CAE changes the normals of the selected elements so that they point in the same direction as the reference element normal.

  7. Repeat the previous steps as often as necessary to reverse additional shell/membrane normals. When you have finished assigning normal directions, use one of the following methods to exit the assignment mode:

    • If you are selecting regions of the part or elements from the viewport, click mouse button 2 or click Done in the prompt area.

    • If you are selecting preexisting sets from the Region Selection dialog box, click Cancel to close the dialog box, then click mouse button 2 or click Done in the prompt area.

    Abaqus/CAE reverts to the render style that was selected prior to starting the procedure to reverse the shell/membrane normals.