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Combine three sheets to one sheet body

Pioneer
Pioneer

Hello!Smiley Happy
Im relatively new to the NX universe but some friends of mine didn't know an answer to my problem, too. In my opinion, it seems to be a simple problem with a simple solution, but we still can't figure it  out.

To break the problem down to a minimalistic equivalent:

 

My main aim is acquire a properly meshed sheetbody with mating meshes on the surfaces in contact. At this point of time, I was not able to achieve a proper mesh without much additional manual work, which is not feasible in an automated process. I guess that the root cause of my problem lies in the part design.

 

It is not possible to revolve a sketched (lying) "Y" (so basically three faces which are in contact with each other on one curve) as a sheet because of the error which states: "...intersecting section...", am I right? So my next try has been to divide the curve into 2 sketchgroups and revolve the grouped courves seperately, so the problem of intersecting sections is avoided. Consequently, two sheet bodies are the result.

How can i merge them into one sheet body afterwards?

Using the command "sew" in the simulation tree does not deliver the desired results either, as the error "Some sheets disjoint from target - try a looser tolerance" pops up.

Via "stitching edges" it is possible to manually connect the faces, but as a consequence, edges have to be (re-)merged for a favourable result.


Furthermore, I've already tried to revolve the curves as solidbodies with an offset of -5/+5mm and united them in order to create a midsurface. Unfortunately, the midsurface is also depicting more than one sheetbody and the meshes aren't mating aswell.

 

Can somebody of you please help me? In the best case, we were just to dumb to see the solution, even if it might be easier than expected.

 

Thank you in advance

 

Kind regards

Benny

3 REPLIES

Re: Combine three sheets to one sheet body

Siemens Phenom Siemens Phenom
Siemens Phenom

Benny,

 

NX Modeling (CAD) operates with manifold geometry only. In your example that means an edge can be shared by no more than 2 faces. That is why you are getting errors in the extrude/revolve commands while using the sketch of the Y. It is also why Sew will not connect 2 sheet bodies that define the Y into a single sheet body.

 

NX CAE solves this problem using the Stitch Edge command with respect to polygon bodies. Stitch Edge allows N number of faces to share the same edge. Note that polygon bodies (sheets and solids) are different from CAD sheet and solid bodies. Polygon bodies are tessellation based bodies created and used only by the CAE applications. They are based upon CAD sheet and solid bodies. Polygon bodies are non-manifold.

 

You can try using the automatic edge-edge stitch method in the Stitch Edge command. I don't know what you mean by "edges have to be re-merged for a favorable result".

 

Regards,

Mark

Re: Combine three sheets to one sheet body

Pioneer
Pioneer

Sorry for my late response but thank you very very much!

 

To the last question:
Everytime I am stitching the model, edges split. (If I am doing it via Stitch Edge-Manually it even states, that edges have to be split). When I am merging them afterwards everything is fine, but as I am planning to achieve an automatable solution and the merging is (in my opinion) not really automatable, this depicts a problem.

Re: Combine three sheets to one sheet body

Pioneer
Pioneer

As I mentioned before, I am still having this problem Smiley Sad

My aim is to create a FEM template model. Everything works fine there with stitching edges and re-merging them afterwards. The Mesh looks great then.  

But as I want to update the corresponding geometry (change some dimensions +-10mm for example), the meshing process fails most of the times. Is this happening due to the model abstraction?

How can I avoid that problem? I read something about wavelinking the geometry but I am not sure if this will work. 

Freeze geometry will not work either as the Stitch command is not applicable after that anymore, am I right?

 

Thank you very much in advance