Custom refinement may duplicate and merge nearby nodes

disla

Hi,

I have found the source of one problem I was experiencing.
Custom refinement on near shells may duplicate some elements and merge nearby nodes.

Attached file shows the problem if you request to custom refine (2,2,1).

Victor

Could you clarify where the problems happen? I don't see any duplicated elements nor the beams merged to the solids or shells when I apply Refine custom to the whole model or to just the shells.

disla

Running the model just opened the plates separate as they are not attached in any means. After a Custom refinement 2,2,1, the nodes between plates are merged and the solution gives cero displacement .

Additionally, internal solver shows a warning.:

Warning: Elements 65, 74-128 ... are duplicates. Use Tools -> Find duplicate elements to show them. .

disla

Hi, Victor,

I think I see what happens. You fixed the custom refinement adding a merge operation as some of the middle nodes disconnect in previous versions. Now , when merging, there is this particular case when two elements that are going to be refined overlap and end up merged together.

Maybe a warning before proceeding if some of the nodes thar are going to be Custom refined are overlapping?¿?. Or maybe proceed as Refine x2. Curiously it doesn't show this problem.

Victor

Oh, I see now. I was somehow looking at the wrong file before. Your explanation does sound like what happened. I'll see about adding a warning in a future version. Fixing it properly will be more difficult than Refine x2 because it has to keep track of more in-between nodes.