Creating or Editing Iso-Thickness Areas

You can create iso-thickness areas (ITA) for an easier and quicker design. For example, define ITA to create an extended top surface used as reference surface for another ply group, or a top surface on an area with no plies, or on a limited area of the plies.

Notes:
  • This task is available in Composites Design.
  • Some options are available only in creation mode.

See Also
About Iso-Thickness Areas
  1. From the Solids and Top Surfaces from Plies section of the action bar, click Iso-Thickness Areas .
    The plies groups found in the model are displayed in the dialog box.
  2. Select a complete stacking or a selection of plies group.
  3. Do one of the following to select points to define the areas.
    • In the spinner under Point Defining Areas, enter the minimum width that makes an ITA selectable and click Compute and select areas wider than...
      Note: The maximum drop-off value is proposed.
    • Select existing core sampling points. Multiselection is available.
      Tip: Although optional, selecting Imposed Thickness Points (ITP) helps manage ramps that do not follow a linear law (e.g. because a manual ply has been added), or ramps at the edge of the part.
    • Pick locations to indicate points.

      Save them in a dedicated work object.

    • Optional: Create more points with the context menu.
  4. For models not designed with a grid approach, define the Drop-Off Values to compute the bottom of slope.

    • Maximum is 0 if no ramp support has been defined, or to the maximum step of slope found in all ramp supports of the model otherwise.
    • Default is 0 if no ramp support has been defined, or to the minimum step of slope found in all ramp supports of the model otherwise.

  5. Optional: Select the Ignore ramp supports check box, when ramp supports have not been defined, or when they do not fit your requirements (The first curve in the ramp support is not the top one, or you need to extend plies by a symmetry).
    • This option applies to the iso-thickness areas group, not to individual iso-thickness areas.
    • When this check box is selected, the shells are relimited by the bottom slope, computed with the distance to neighboring ply contours, with a geometrical approach.
    Note: If this automatic computation fails, you can relimit specific shells using standard relimitation commands.
  6. Under More, select a contour or Composites geometry and the required method to create limits.
    • Iso-Thickness Area: Creates the ITA group only inside the selected area (one selection permitted). The top surface generated from this ITA group is limited by the contour or geometry.
    • No Thickness Area: Creates the ITA group with all the areas found inside the selected contour or geometry, even it the areas have no plies, thus no thickness with respect to the support surface. The top surface generated from this ITA group contains these areas with no thickness.
      Note: Make sure the Not Thickness Area does not intersect a ply contour.
  7. Still under More, extend the limits of the ITA area.
    • User Define: Select an Extended limit (Contour or Composites geometry), and an optional Start EOP (Contour or Composites geometry) to specify the side of the ITA to extend.
      Notes:
      • If you do not select a Start EOP, it is computed as the full ply boundary of all selected plies groups.
      • Start EOP and Extended limit are larger than all selected plies.
    • Auto: Enter an offset value (Extended limit and Start EOP are automatically computed).
      Notes:
      • The offset value cannot result in a top surface larger than the support surface.
      • Auto does not support multi-domains EOP.
  8. Under Other Outputs,
    1. Select the Generate shell boundaries check box.
      Shell boundaries are automatically computed for each iso-thickness area shell.
    2. Select the Generate offset surface check box.
      An offset surface is automatically computed for each iso-thickness area shell.
  9. Under Modifiers define an Additional thickness ratio.

    • It is entered as a ratio of the current thickness, for example 0.1 means 10% of the current thickness.
    • In creation mode, it defines the additional thickness of all the iso-thickness areas of the group.
    • In edition mode:
      • If an additional thickness previously applied to all the iso-thickness areas of the group, the modified additional thickness applies to all the iso-thickness areas of the group.
      • If an additional thickness applied only to some iso-thickness areas of the group, you can choose to apply the modification only to those iso-thickness areas or to all iso-thickness areas of the group.

    By default, the additional thickness ratio is 0.

The iso-thickness areas group and the iso-thickness areas are created.

Note: The contour of the iso-thickness area is relimited by the bottom of the ramp (that is, last ply+1 on ramp support) if the plies are created with the grid approach (that is, if they are based on ramp support). In that case, the iso-thickness area turns yellow. If the iso-thickness area cannot be relimited by the bottom of the ramp, it turns pink.

A warning is issued if an iso-thickness area needs to be reworked.

You can modify the shape of an iso-thickness area before creating the solid.

When the core sample point of an iso-thickness area may have become invalid, a symbol at the iso-thickness area node indicates that the feature needs to be updated.

If you modify an iso-thickness area, and add or modify core sample points, iso-thickness areas that have not been impacted do not need to be recomputed.