Meshing Octagonal Part- Face Angle less than 45 degrees
Meshing Octagonal Part- Face Angle less than 45 degrees
(OP)
Hi,
I am modeling an octagonal foundation in Abaqus. The foundation is 3.1 m in height. By its geometry, foundation has got slopes with face angle less than 45 degrees. As a result, when I mesh my model, I get a warning which says that distorted elements have been detected. This is around 25% of total no of elements. How can I partition/seed, etc. to reduce the no of distorted elements? I cannot compromise on the geometry of foundation. Attached is the mesh photo and distorted elements are highlighted.
The four tetrahedron shapes at each of 4 corners are causing the problem. I tried bottom up meshing also but only in vain.
Please suggest. Thanks.
I am modeling an octagonal foundation in Abaqus. The foundation is 3.1 m in height. By its geometry, foundation has got slopes with face angle less than 45 degrees. As a result, when I mesh my model, I get a warning which says that distorted elements have been detected. This is around 25% of total no of elements. How can I partition/seed, etc. to reduce the no of distorted elements? I cannot compromise on the geometry of foundation. Attached is the mesh photo and distorted elements are highlighted.
The four tetrahedron shapes at each of 4 corners are causing the problem. I tried bottom up meshing also but only in vain.
Please suggest. Thanks.





RE: Meshing Octagonal Part- Face Angle less than 45 degrees
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
I am using C3D8R elements and C3D6 elements. More than 99% elements are C3D8R elements. I prefer using these elements because so far in my previous analyses I have got good results with these.
I will try using your suggested method of partitioning and see what happens. Thanks.
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
Fig 3 shows the partitioned tetrahedron at one of the corners and the plane is also removed. However, some part of the tetrahedron is left unmeshable(orange color). May be this is not the way you suggested to partition. Can I send .cae file to you? If yes, how can I do it.
As you can understand from Fig 1 & Fig 3, I am able to do meshing but my main concern is distorted elements at the boundaries. Thanks.
Fig 1
Fig 2
Fig 3
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
Why you've left the plane that causes the wedge shapes in is a mystery. If you don't need that for material assignments, then remove it. All the problems of bad elements will then go. The only bad aspect of removing that plane is that the element shapes will taper down to the outer edge with a structured mesh. There's probably a way round that by defining the regions as swept.
You can attach the .cae file here but delete all the elements beforehand so as to reduce the file size.
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
Fig 1
Fig 2
Thanks.
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
Fig 1
Fig 2
Fig 3
Thanks.
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
All I did was to remove the feature that defined the wedge shape and then had to tidy up a few partitions as deleting anything in Abaqus seems to mess things up a bit. In the mesh module all the cells were structured regions. I used a mesh size of 0.25 rather than the 0.5 you used as this gives a better mesh size around the circular region inside the model. Note you'd have to reassign your material sections in the property module and also note that the section 'concrete' is missing.
When I did the mesh verification there was still some elements that would give warnings but there's not much you can do about that with the geometry and the elements didn't look that bad to me. Dividing the triangular regions up into 3 regions as you did wouldn't help either.
Attached are some pictures showing a wireframe of the partitions, and the final mesh.
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
Secondly, you can edit the file in 6.13 and send it to me. In my lab I have this version. On my laptop, however, I have 6.10. That will allow me to exactly see what you done. Thanks.
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
RE: Meshing Octagonal Part- Face Angle less than 45 degrees
RE: Meshing Octagonal Part- Face Angle less than 45 degrees