A lot of designers have been using tetra element meshing kind of “by default”…
When you see and hear everyone around you telling that automatic tetra meshing is the most convenient and easy way to get your model meshed, it’s tempting to just do that.
But in fact, automatic tetra meshing has always been kind of a marketing hype propagated by FEA software company to tell everyone how much they product is fast and easy to use.
I am not telling it is not good… I am telling there is better out there.
Now…if you are a real engineer here’s what I advise you.
Try to create manually a nice and smooth brick meshing and I promise that you will see the difference:
- In terms of computational efficiency
- In terms of accuracy
To show you how to actually do that, I decided to show you one of the simplest examples I could find…a valve stem.
So here’s the nice brick mesh we will try to get:
Brick meshed valve stem
How did I do that, very simple… so simple that I decide to make a very short video to show you the actual process. You will not believe how much it is actually easy to create such a nice and smooth brick mesh.
BTW, I am using a software called midas NFX, but the same procedure is also reproducible easily with other software available on the market.
Conclusion:
A nice and smooth brick meshing takes really not much effort to build and provide an incredible increase in both accuracy and performance.
Some additional notes:
- If the geometry cannot be easily broken into components for brick mesh, unfortunately, tetrahedral mesh is still the best acceptable way to fill a volume
- Some pieces of software provide also tetra-brick hybrid meshing, but this kind of meshing is not standard
Let me know if this article was useful to you in the comments! It’s always nice to receive any kind of feedback (Good or Bad ;-) )
–Cyprien
I have a problem, won’t be any problems with the central part, the elements will be very dense near the central line
To make a better Center, use the Technique to Hexham Mesh Espheres.
Cut the solid in the Center and extrude mesh it with Hexas. Then, you revolve mesh like he showed in the video, using the nodes of the circunference as a reference.
Right now am learning brick meshing. This article is most useful to me.
Why not tet mesh,most researchers say there’s only 5-10% diffence in accuracy between second order tet and Hexa(brick) meshing!!
Can you explain with more pros and cons?
Don’t believe what “Researchers” say… try by yourself. Make a small plate with a hole model and compare the results between different types of mesh and also between first and second order. Then you will see the difference. Read this article for details. It is true that 2nd order tet mesh is generally accurate enough, but it also require more nodes than a brick mesh first order (so more computationally demanding) and it is an unstructured mesh… If your purpose is to analyze a pressure vessel shell for example, brick mesh will allow you to be sure you have exactly the same number of elements in the thickness all around your model. If you mesh that with a 2nd order automatic mesher, you will not get that.
Do you have data or test information to corroborate your statements that the brick mesh is better :
In terms of computational efficiency?
In terms of accuracy?
The reason I ask is because I worked for a company in the nineties that did conduct some benchmark testing and they published information showing the equivalence of the two element types in terms of accuracy. I am not blasting you, I just want supporting scientific testing to validate the claim. My customers ask me about it sometimes. Thank you.
Hi Anthony, This is a great question you are asking. In general, yes, hexa are much better than first order tetra because the interpolation of the solution from the nodes is quadratic while the interpolation is linear for a tetra element. You can read (and try) the simple example presented here: http://feaforall.com/fea-basics-plate-with-a-hole-analysis/
Now, I am talking mostly about structural analysis when I say that…but if you talk about CFD or nonlinear explicit analyses, things can become a bit more tricky. Some Finite Element CFD codes may be optimized for tetra, while other codes can be based on finite volume method and be optimized for hexa… In this case, you’ll have to look into the manual of the software/code you use to see what’s best… or do your own testing :)
Thanks, that was really helpful…just found your blog…amazing content…