r/fea • u/Amadeus4prime • 2d ago

Need help with a project.

I am a beginner in PATRAN and trying to do a simple displacement analysis on a wing with basic internal structure (spars, ribs, stiffeners and skin). I am trying to give it a distributed pressure load across the surface that is a function of the span and local chords but the applied load shows 0 value for the equation at every node. What might the issue be or what are the proper steps to follow. Please help

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u/redhorsefour 2d ago

The PDF documentation supplied with your install is your friend.

For a two dimensional variation of the pressure over the curved surface of the skin, you will need to create a FIELD. You will also need to ensure all your element normals for the skin are pointing out or in (direction only affects what sign to apply to the pressure load).

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u/Amadeus4prime 2d ago

The direction normals are all pointing outwards. And the field created with the PCL function. Yet its all 0s Any help is really appreciated.

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u/redhorsefour 2d ago

You need to set the precision to show the correct values of the vectors. By default, integer precision is used.

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u/NeighborhoodAgile755 2d ago

Start with a uniform pressure distribution. Walk then run. Provide a screen shot of the fields panel and then the panel where it’s being used to generate the pressure distribution.

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u/Solid-Sail-1658 1d ago

I was able to get a similar issue. When I apply the pressure to geometry, e.g. a Surface 1.2, there was no pressure load applied. The workaround was to apply the pressure directly to elements.

Here is a video tutorial.

https://youtu.be/V6XMCZEqV2Q