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How to Resolve Ply Producibility Problems in Fibersim

by Community Manager Community Manager ‎11-15-2016 09:03 AM - edited ‎02-15-2017 10:51 AM

When attempting to resolve producibility problems with a given ply in Fibersim, you have many options outside of changing the basic surface geometry:

  1. Change the propagation settings – while this may help, it is critical that the propagation settings match the layup procedure on the shop floor to ensure an accurate flat pattern.
  2. Move the origin – this frequently has the largest impact, though may not be feasible on the shop floor.
  3. Splice the ply – smaller pieces will usually drape more easily, but this may not be allowable from a stress or weight perspective.
  4. Dart the ply – darting may not be an option in critical areas

Assuming you have already ruled out 1 through 3, the question becomes: “How do I apply darting to this particular ply?”  It turns out that Chapter 2 of the Fibersim user guide actually has a wealth of information on how to interpret producibility and apply darts based on the type of wrinkling encountered.  It can be found with your Fibersim installation (%FIBERSIM_HOME%\FiberSIM\documentation) or by accessing the help menus via the UI.  Some highlights:

Determining deformation type (Wrinkling vs. Bridging)

  1. Trace a line from the ply origin through the deformed cell
  2. If the deformed cell elongates along that line, it is a wrinkling condition, caused by too much material
    1. Apply a slit dart to remove excess material
  3. If the deformed cell shortens along that line, it is a bridging condition, caused by not enough material
    1. Apply a V dart to allow material to open up around the problem area

DartingGuidelines1.png

Remember, the dart type refers to its 3D shape, which actually has an inverse relationship to its 2D shape:

  • A Slit Dart is a 3D slit, but will typically be an open V shaped cut in the flat pattern.
  • A V-Shape Dart is an open cut in 3D that must be patched, but will manifest in a 2D slit in the flat pattern.

Effective Slit Dart depth

  1. Find the first non-red fiber path on either edge of the red region
  2. Trace them back away from the boundary to find the intersection
  3. Use the intersection as a starting point for your slit dart

DartingGuidelines2.png

 V-Shape Darts

For V-Shape Darts, the best practice will depend on the design limitations you have.  Since you are effectively removing an area of ply coverage, a patch will likely need to be created to fill it, which may necessitate enlarging the area to make the patch structurally viable.  This makes it impossible to provide a generic guideline for effective sizing.  Just make sure that the resultant flat pattern doesn’t overlap itself!