Question: My flat patterns appear to be wavy. What is causing this?
Product Tip: When experiencing wavy or "bad" flat patterns, the first step to troubleshoot the issue is to verify producibility. Make sure that there are no distinct irregularities within the simulation fibers near the wavy areas of the flat patterns. Verify that producibility is completing through to the outer edges of the ply and that it covers the whole surface being defined in the ply area.
Next, try decreasing the value of the Fiber Spacing Factor found in the Simulation Options Tab for the ply with the wavy flat pattern. The lower the value, the tighter the fiber simulation will be in relation to the surface resulting in more accurate flat patterns. Re-run producibility and inspect the flat patterns to verify sharper, more accurate patterns. FiberSIM requires the Fiber Spacing Factor to be 0 < FSF < 10. Note, however, that decreasing the Fiber Spacing Factor will increase producibility time.
A main cause for wavy flat patterns and poor producibility is poor surface quality. If the surface is rough or rugged, simulating fiber paths over crevices on the surface can cause issues with flat patterns, as well as producibility.
To inspect for poor surface quality within:
CATIA V5
There are two methods used to inspect the surface quality using the CATIA V5 CAD system: Porcupine Curvature Analysis on a curve projected onto the skin or a Parallel Curve referencing the ply boundary edge using the skin as support.
The Porcupine Curvature Analysis uses a curve that can be created in FiberSIM using the Curve Creation Functionality under the Utilities drop down. Once the curve has been created on the skin, in CATIA go to Insert/Analysis/Porcupine Curvature Analysis. Select the created line and a plot of the surface will appear. The analysis will determine any non-tangencies on the skin.
Using the Parallel Curve option, go to Insert/Wireframe/Parallel Curve in CATIA. Select a curve or the net boundary curve, and then select the skin as the support. The error message, "Parallel #: Topological Operators: internal errors" might appear. The error message verifies that there is a problem with the surface. The Parallel Curve method is not as accurate and detailed as the Porcupine Curvature Analysis.
Pro/ENGINEER
A method to inspect surface quality using Pro/ENGINEER is the functionality called Curvature. Go to Analysis/Geometry/Curvature. Select a surface where the user wants to inspect the surface. A plot of the surface displays. The analysis will determine any non-tangencies on the skin.
NX
There is one common method used to inspect surface quality in NX. This is known as the Hedgehog Analysis under the Analysis/Shape/ Face/Slope dropdown. Once in this functionality, you can select the vector construction that you would like to perform the analysis on. A second window appears after you have chosen the preferred vector construction. In this second window you will be able to choose which faces you are to perform your analysis on. You can also manipulate the display surface resolution in this window. After you have completed the analysis, you can simply view what your surface topology looks like and turn its visibility on and off.
For more information, please contact VISTAGY Product Support & Implementation Services at:
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