About the FLEX Algorithm

Computing segments using the FLEX algorithm gives them a more realistic behavior that reflects segment stiffness.

This page discusses:

See Also
Starting from Scratch in FLEX Mode
Updating an Existing Electrical Branch Geometry

How the Algorithm Works

Based on segment properties (length, diameter, etc.), CATIA computes the effective Young modulus and other input needed by the algorithm (cross section shape, flexibility, etc.).

The FLEX algorithm allows you to create smoother FLEX curves when generating new branches. It takes into account protective coverings, conductors and conductor groups:

  • If no conductors or conductor groups are routed, segment stiffness is based on individual segment flexibility.
  • If conductors and conductor groups are routed, segment stiffness is based on the properties of the conductors and conductor groups. In this case, individual segment flexibility is ignored.

If no FLEX solution can be found, a message is issued and the standard algorithm is used.

The electrical designer can take advantage of all the benefits of the FLEX algorithm while working exactly in the same way as with the standard algorithm.



Legend:
  • Standard algorithm: yellow
  • FLEX algorithm: blue

Protective coverings add stiffness. This is taken into account by the FLEX algorithm.

Standard algorithm

FLEX algorithm

Note: To use the FLEX algorithm, you need a FLEX Physical Simulation license. For more information about this product, see About Flex Physical Simulation.

Splice Attribute Integration

A splice is an electrical connector allowing to connect several conductors together. Internal splices add stiffness.

The FLEX algorithm takes into account the values for the Length and Equivalent Thickness attributes entered when defining splices in Electrical 3D Part Design.

Important: You need to update an existing electrical branch geometry to take into account modifications to length and equivalent thickness of reference internal splices, and to replace an internal splice by another one.

Before you begin

These functionality require a FLEX Physical Simulation license. For more information about this product, see About Flex Physical Simulation.

These functionality are accessed by setting the Segment Computation to FLEX algorithm and adjusting the balance slider.

About the FBDI Import

In 3DEXPERIENCE, if the splice is inside or outside the segment, it is treated:

  • like an internal splice: the splice is linked to the end of the segment through the Segment Position Point > Splice Position Point.
  • like an external splice: the splice is linked to the end of the segment through Connector Point.

To connect a splice to a segment:

  • A Splice Position Point is created a the extremity of a segment.
  • The splice is aggregated at a segment position point.
  • A coincidence constraint is created between the two connection points.

About curvature artefacts, the FLEX curve is versioned:

  • If the FLEX curve is generated before R207, it will not be modified except if the user does it manually.

  • The FLEX curve of the segment will be computed with the new algorithm.

Flexibility

The flexibility of a segment can be defined using two modes.

  • The Standard mode enables you to set a low or high flexibility using a slider.
  • The Material mode allows you to set the flexibility of a segment using the properties of a material.

Material Definition

A material has to be defined with a Simulation domain. It is the only material domain supported by the app.

In the Material Definition: Simulation Domain dialog box, the following options must be selected:

  • Density
  • Elastic (Under Mechanical > Elasticity)
    Important: The Elastic input must always be of Isotropic type, and the Young's Modulus and Poisson's Ratio must be defined.
  • Expansion (Under Mechanical)

For more information about Simulation domain definition, see Structural Validation User's Guide: Defining a Simulation Domain.

Material Management

Once the material defined, it has to be applied on the segments of a branch using the Material Browser command.

For more information, see Material Definition User's Guide: Managing Materials with the Material Browser.

During the computation of the centercurve, the applied material is taken into account and is reflected on your model after the update.

Important: If the simulation domain options are not consistent, the standard mode is applied instead and a warning message is displayed after the update.

Notes:

Computed Bend Radius

In FLEX mode, CATIA computes the effective minimum bend radius because the algorithm's input is the physical properties of the segment (diameter, etc.) rather than purely mathematical parameters.

The bend radius, which is therefore no longer an input, is an attribute of the segment used for checks.

Status lights (red / green) show whether the Computed Bend Radius satisfies the minimum bend radius entered.

Constrained Length Build Mode

The constrained length mode helps you minimize the impact on manufacturing.

For example, in this mode, modifying the position of a support in the work area does not modify the flattened view or the harness drawing.

The constrained length mode lets you keep the same segment length between points, branch points, supports and devices during harness design and modification, when moving, replacing or deleting a support, device or point.

For example, move this support:



and the length of the segment does not change:



In this mode, you can set the percent tolerance allowed between the initial and final segment length. For example, if you set this value to 1 and the segment is 100 mm long, then a final length of 101 mm will be tolerated.

Note: In Constrained Length mode, the default accuracy is set to a very high value to respect segment length better. The value set for the balance slider is not taken into account.

A message informs you if the modification in a segment length exceeds the tolerance and identifies each concerned branch.

This build mode is recommended once you are well advanced in your design because you cannot:

  • Add slack, supports, devices or branch points
  • Split segments
  • Merge branches
  • Modify the length of a branch
  • Move a branch point.

Indeed, these actions impact the length of the segment and CATIA cannot figure out how you intend to modify this length.

Local Slack

You can add local slack to the electrical branch geometry.

You can add local slack at a specific location using Local Slack in Electrical 3D Design. However, the Ignore Slack option is not supported by the FLEX algorithm and is not available in the Local Slack Management dialog box.

Existing Harness Update

You can re-compute, using the FLEX algorithm, harness segments designed using the standard algorithm:

  • Set the segment computation mode to FLEX algorithm and adjust the balance slider.
  • Click Segments Centercurve and Segments Diameter in the Electrical 3D Design app to recompute all segments.

    All segments are highlighted in red in the work area meaning they need to be updated.

  • Select Update to rebuild segments using the FLEX algorithm.

Notes:
  • If no FLEX solution can be found, a message informs the user and the standard algorithm is used.
  • You can undo the recompute operation before or after the update.
  • If you update branches with internal splices that were designed in previous releases, the branch shape may be slightly different because the FLEX algorithm takes internal splices into account.
  • The branchable created with a particular option in the Segment Computation area in Me > Preferences > App Preferences > 3D Modeling > Electrical and Electronic Systems > Electrical 3D Design > Branch has its electrical curve built and updated with the same algorithm throughout its lifecycle. Switching from one algorithm option to another has no impact on the geometry of the existing electrical curves. If a branchable is edited, then its curve is updated based on the internal algotype attribute value which is set during its creation.
  • Using Segments Centercurve and Segments Diameter commands, you can switch the algorithm options of all branchables according to the one specified in the Segment Computation frame.

Design Range Management

The FLEX algorithm should not be used in a large range context. It is highly recommended to use the normal range when designing an electrical branch geometry with the FLEX algorithm.