Showing results for 
Search instead for 
Do you mean 
Reply

Behavior of surfaces which have load applied (or which have other associated data)

I've been frustrated with how FEMAP handles load on faces. Two major gripes:

 

  1. When a face with load applied is split (e.g. via Point to Edge split, or nonmanifold add, or Project Curve etc.) the resulting new faces do not inherit the load from the parent. This has led to mistakes in our results. The newly created faces should inherit the load from the parent. Similarly, such new faces should inherit the original surface's group. I keep a group of faces which are to be loaded with pressure, and the current behavior breaks that (silently). The new faces should inherit all properties of the original face.
  2. If a face has applied load (e.g. pressure, or is part of a nonstructural mass region) then FEMAP will not allow me to delete that face until I remove all load from it. When I have e.g. 16 load cases, this means I have to go in and change each one to exclude that face before deleting it. This has been costing me a lot of time.
    ALSO: The error message says that "Deleting the face would lead to a non-rebuildable solid" (loose DE>EN translation) instead of "The face has associated loads applied and cannot be deleted" - although even better would just be to delete it and remove all references to that face in the load cases.

We are still on v11.2.0 but will soon be on v11.3. Has anyone noticed improvements in this area?

2 REPLIES

Re: Behavior of surfaces which have load applied (or which have other associated data)

Dear Kava,

Do not get frustrated, this is the way of running FEMAP, once you are aware of the "philosophy" of FEMAP you will realize that things are in general so easy, and simply, like us!: as a rule of thumb the properties, loads & constraints should be defined or prescribed at the final phase, first you need to get both geometry & mesh density & mesh quality well defined (I play a lot with PLOT-PLANAR elements), and next define properties and prescribe loads & BCs.

Before launching the FE analysis solver you need to revise your FE model, making sure that properties, loads & BCs are correctly defined, not excuses here, activate the HIGHLIGHTER icon, this way when you pick in any property, load or BC the entities are highlighted in the screen, this is an easy way to check your FEMAP model.

 

highligther-vector.png

Regarding deleting surfaces or faces of solids:

  • You can delete solids, or Nonmanifold bodies, then FEMAP will ask you "OK to delete Associated Properties, Loads, BCs, Connections, Mesh as well??". If you say YES, all will be deleted.
  • But if you try to delete an isolated surface with loads or BCs part of a NonManifold-Add body, then FEMAP don't do it, this is to protect your model.

Yo can delete a surface of a 3-D solid, yes, but caution!: this way the solid changes from regular solid to Sheet Solid body, only meshed with 2-D Plate elements.

 

Of course, I recommend you to install the new version of FEMAP V11.3 as soon as possible, at geometry Parasolid level is much more robust than any previous version, really, really powerful, good job FEMAP guys!.

Best regards,
Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: Behavior of surfaces which have load applied (or which have other associated data)

I understand your perspective, but hope that FEMAP becomes easier to use in the future when it comes to model updates. It should not be so hard to simply delete a face out of a midsurface model.