Help me mesh this part, C3D8 element.
Help me mesh this part, C3D8 element.
(OP)
Dear FEA experts,
I need to mesh this part in C3D8 elements, but I'm getting a large number of element warnings (~13%) and my simulation terminates midpoint due to excessive element distortion. I have also tried C3D4 Tetrahedron elements but they give a stiffer result.
Please download the part here - https://www.dropbox.com/s/i5bx63wb43ewqil/Part.sat...
Somebody please help!
I need to mesh this part in C3D8 elements, but I'm getting a large number of element warnings (~13%) and my simulation terminates midpoint due to excessive element distortion. I have also tried C3D4 Tetrahedron elements but they give a stiffer result.
Please download the part here - https://www.dropbox.com/s/i5bx63wb43ewqil/Part.sat...
Somebody please help!





RE: Help me mesh this part, C3D8 element.
RE: Help me mesh this part, C3D8 element.
RE: Help me mesh this part, C3D8 element.
RE: Help me mesh this part, C3D8 element.
RE: Help me mesh this part, C3D8 element.
RE: Help me mesh this part, C3D8 element.
Do you suggest me to use C3D10M instead of C3D8/C3D8R? What about accuracy and computational cost? Note that, I'm using ABAQUS/Explicit for a high strain rate event simulation.
RE: Help me mesh this part, C3D8 element.
In my experience I've tended to ignore warnings about element shape of brick elements unless they were in a region that was of particular interest but if they're particularly flat or a peculiar shape then I'd rectify the mesh, if possible. You can usually tell if you've got poor results by looking at result's contours to see if they appear to be mesh dependent.
RE: Help me mesh this part, C3D8 element.
http://129.97.46.200:2080/v6.13/books/gsk/default.htm?startat=ch04s02.html
RE: Help me mesh this part, C3D8 element.
In summary: there is no quadrilateral bricks in ABAQUS/Explicit, only linear bricks (C3D8R, C3D8 and C3D8I). The order of complexity and computational cost associated with these 3 elements are - C3D8R < C3D8 < C3D8I. C3D8R exhibits hourglassing but its computationally cheap, the rest 2 do not have hourglassing problem but much more computationally expensive since they are fully integrated.
Now, I'm using C3D8R and getting errors, see the image of a small part of my actual structure - http://i.imgur.com/MBaPziy.jpg
I'm getting 1 warning at the beginning of the analysis (White circle)-
18432 elements are distorted. Either the isoparametric angles are out of the suggested limits or the triangular or tetrahedral quality measure is bad. The elements have been identified in element set WarnElemDistorted.
And Analysis terminates as soon as the rigid plate touches the sample (Black circle). Note that its a drop impact test simulation -
The elements contained in element set ErrElemExcessDistortion-Step1 have distorted excessively.
There are a total of 2 excessively distorted elements
The elements contained in element set ErrElemExcessDistortion-Step1 have distorted excessively.
Abaqus/Explicit Analysis exited with an error - Please see the status file for possible error messages if the file exists.
RE: Help me mesh this part, C3D8 element.
RE: Help me mesh this part, C3D8 element.
The full model is bit confidential, I will email you personally if you don't mind.
RE: Help me mesh this part, C3D8 element.
I have tested my model with (all) C3D4, C3D8, C3D8R and C3D8I elements. See the below picture of load-displacement curve of the structure. The Red line is the experimental load-displacement curve, you can see that C3D4 (Tetra) and C3D8I (Hexa, incompatible) elements give better result but it is not good enough.
Can you please suggest how can I improve the result, especially the meshing? One thing to note is, there are elements with warning at the joints for all cases (for all Tetra and Hexa elements).
RE: Help me mesh this part, C3D8 element.