Adding a Stagger Origin Point

You can add stagger origin points to avoid, or at least minimize, the overlapping of the tape and tow junction (chimney effect) that would locally reduce the material strength.

Note: This task is available in Composites Design and Composites Manufacturing Preparation.

See Also
About Stagger Origin Points
  1. From the Producibility and Splicing section of the action bar, click Stagger Origin Points .
  2. Select a plies group.
    The plies group is divided into homogeneous sets of plies that share the same rosette, valid orientation, reference point, and a common area of the reference surface with another ply of the set.
    • They are listed by their index in the second column (Homogeneous set).
    • Two plies that share the same common area are linked.
    • Filters are now available, based on the Homogeneous sets, Rosette, Reference point and Orientation of the plies.
  3. Select a line in the dialog box to highlight the corresponding ply in the work area.


  4. Click COMPUTE.
    Stagger origin points are computed.

    When the computation is done, selecting a ply in the dialog box highlights it in the 3D area.

    For stagger index =0:

    • Starting from a reference point, a geodesic line is created on reference surface using fibber orientation (for example -45 degrees) given by rosette transfer.
    • Geodesic curves parallel to a previous reference curve are created on surface with a geodesic distance equals to Material Width plus Gap. Those parallels are extrapolated up to the surface limits if needed.
    • Intersections of these parallels with Ply.14 (rectangle in fat pink) are computed.
    • Segment for origin point (solid pink line) is defined as the centered intersection.
    • Origin point is the middle of this segment.
    • For the following indices, the same computation is applied, but the first parallel is offset by a distance equal to the Minimum Stagger Value.


    Information about the computation is given in the dialog box.

  5. Used the status and diagnostics from the computation to modify the parameters and restart the computation.

    • Stagger index, that is, the integer value associated with a ply to define the position of its origin point with respect to the reference point:
      • with minimum stagger indices: Only minimum stagger indices are used, that is, 0 and 1.
      • with maximum stagger indices: More stagger indices can be used (Listed under Homogeneous set).
        Note: Two linked plies cannot have the same index.
    • Minimum Stagger Value (MSV): Distance between two stagger indices for an optimum shear strength.
    • Width of the material (tape width).
    • Gap between two adjacent tapes.
    • Minimum nb plies must be located between two plies with the same stagger value in the same homogeneous set of plies.
    • Tolerance between manual origin point and stagger origin point computed from the stagger index.

    By default,

    • Minimum Stagger Value (MSV) is 20mm.
    • Width is 100 mm.
    • Minimum nb plies is 4.

  6. Select one or several plies in the dialog box.
  7. Under Point management, modify the Reference point.
    1. Place your cursor in Reference and select a point in the work area to replace the current reference point of the plies selected.
      The modification applies to all the plies selected.
    2. Click reset default to revert to the default reference point, that is the origin of the ply rosette.
  8. Modify Origin:
    1. Place your cursor in Origin and select a point in the work area to replace the current origin point of the plies selected.
      The modification applies to all the plies selected.
    2. Click reset as computed to revert to the computed origin point.
  9. Modify from Stagger index provides a list of the indices used for the computation of stagger origin points. Select one index to change the current one.

    When one ply only is selected, the list proposes only the indices that do not lead to an error, whereas all values are proposed when several plies have been selected.

  10. If required, click Export table... to export the result as a file as explained in Import, Export, and Manage External Data, both for the location and the format.
  11. When stagger origin points already exist in a plies group, start Stagger Origin Points and click CHECK to verify their validity.

    You can then edit them as explained above.