Gaps between Extruded surfaces in ProE

[peglor]

I'm currently working on a simplified model of a cylinder with angle irons welded around its circumference. A basic drawing is available here:

http://www.csn.ul.ie/~ceason/proeng/cylinder.jpg

The cylinder is made by extruding a trimmed circle to make the first surface. The angle irons were drawn and extruded on seperate sketches.

I plan to export the surface model to ProMechanica (Via IGES, Integrated mode doesn't seem to support surfaces at all) for analysis as a shell element model, but there are gaps between the surfaces defining the angle irons and the curved surface. I have checked and the extruded angle iron sketch is constrained to have its endpoint on the cylinder. ProM's Autoassociate isn't able to fix the problem after the surfaces are imported either.

I've looked at ProE's merge/intersect options for surfaces, but they won't join the surfaces without trimming at least one of them. All the surfaces shown in the picture are needed for the model.

The best solution I've got so far is to export the model as a wireframe, redraw the failed edges or edges with extra vertices (that shouldn't be there) and add the surfaces as quad and tri patches.

Incidentally, Is there an option somewhere to allow ProE to generate a surface from a loop of 4 non coplanar curves? I've found the one to do more than 4. Is there an equivalent to the Quad and Tri Patch options on ProMechanica in ProEngineer?

I'm relatively new to the surface features of ProE, mainly because I've never needed them, so all advice will be appreciated .

 

[im4cad]

To create your surface from 4 non coplanar curves (their ends must intersect, so you should have a closed “wireframe”) use the advanced option:
Feature --> Create --> Surface --> New --> Advanced --> Boundaries --> Done --> Blended Surf --> Done
Choose two of them for the first direction and the other ones for the second direction.

Using “Merge” or “Join” for surfaces is for creating closed quilts, that’s why you have that problem. You can’t merge surfaces and have multiple closed volumes in the same quilt.


im4cad
Pro Design Services, Inc.

http://www.cadproe.com/pds/home.asp

 

[noppenbd]

Have you tried extending the angle iron surfaces and then trimming them back with the cylindrical surface?

 

[sundevil98]

If the problems above didn't help, you may want to try and crank up the accuracy of the part #Setup #Accuracy. I think the default is .0012 Try something lower like .0003 or even .0001 (the bigger the part though, the longer it'll take to regen, but yours looks like it shouldn't have a problem).

Also, I think there's a way to "zip the gaps" between surfaces, but I haven't yet found or used this feature, I've only read about it.

 

[PaulJG]

Hi, I could'nt access your model either so I built it from scratch in version 2000i with guessed dimensions and had no problems with it meshing in Pro/FEM with the default accuracy of 0.0012, I think you may not be referencing the cylinder properly when you are sketching the angle irons, even though you cant see the surface in sketcher because it is thin side on to you you can tilt the model slightly in order to reference it in sketcher. This makes sure that the suface edges are coincident and can be properly meshed together. Using merge is not a very useful technique with your geometry because merge will try to get rid of one surface when it gives you the option of side 1 or side 2 to keep. Join is the same. If you wanted to create a single merge quilt then you would have to rebuild the "lost" surface after the merge or join process, however I found that Pro/FEM meshed the shell model correctly without having to merge all surfaces together.

Best regards