PrePoMax & CalculiX - Submodel
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- Опубликовано: 11 сен 2024
- Using sub-modelling it is possible to analyze in greater detail only a part of the whole structure. In this video, an example of how to prepare the global model and sub-model using PrePoMax pre and post-processor for CalculiX FEM solver is shown.
Download link and installation instructions for PrePoMax: lace.fs.uni-mb....
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Congratulations on version 1.0 of your fantastic and extremely useful program!
Thank you, Ihor!
nice, I waited for this feature. and the implementation in the gui looks again quite easy and professional. thanks for all this work!
I understand. You indicated the results from the first calculation as the support conditions for the entire model. Epic. Bravo.
Yes, that is what sub-modelling is all about. But it is a standard CalculiX feature so thumbs up for CalculiX.
This software is very helpful and easy to use.
Hi Matej, I was seeing in this case that the load on the submodel is a pressure towards Y positive direction (ruclips.net/video/-GcpCNbBcA8/видео.html), but the deformated model looks like is in Y negative direction (ruclips.net/video/-GcpCNbBcA8/видео.html), could it be, or I'm wrong?
You are right. It is wrong. I checked the model again and I made a mistake. The mistake was that the global results file was changed between the first and the second part of the video. I was testing different load directions which changed the correct global result. I also checked that it works as expected if you do it right. The question is should I make it right or leave it as a reminder :)
@@MatejBorovinsek maybe you can add a note or something similar in the video, don't know I youtube have a tool to do that
@@4pingenieria81 It seems the tool was removed. So I will leave the video as it is and test how many users notice the mistake :)
@@MatejBorovinsek Maybe the easier would be adding a note on the video description
Very well implemented the submodeling option!. One question, the initial model has to be partitioned in the submodeling volume?
There is no direct connection between the geometry of the global model and the submodel. The submodel boundary condition determines the displacements from the result file based on node coordinates only. So the submodel only needs to be in the right position - inside the global model.
Спасибо
It’s great that you’ve added shell edge load, that’s what I just needed. Too bad CalculiX doesn’t support shear/traction type for this load.
By the way, have you encountered the error „The file ...\Temp\geometry.vol does not exist. The reason is failed mesh generation procedure for part ...” ?
It occurs even for very simple geometries and with correct mesh size (not for all sizes and not each time though).
The error you describe is a failed mesh generation in Netgen. But you should always get the same result. If the meshing parameters are appropriate, you should always get the mesh. If the meshing parameters are not appropriate, the mesh procedure should always fail.
@@MatejBorovinsek Thanks for reply. As an example, I have a model of a square section beam 40x40 mm (1 m long). And if I use mesh size of 20 mm in PrePoMax, I get this error and mesh is not generated (even though the preview looks fine). Interestingly, it seems that it doesn’t happen on another computer.
You can use the Surface traction load on the edges from version v1.0.0 on. But the selection can only contain edges.
@@FEAnalyst Are you using Windows 10. I did not notice such behaviour before.
@@MatejBorovinsek But this shell edge load has to be normal to the edges, right ? I was rather thinking about a load tangent to the edge (shear).
(Translator) Without the submodel option, you can also cut a slice and analyze it. What does a submodel give? Smooths displayed stresses or changes boundary conditions? It looks as if you asked flexible supports. How does the program know what is supported in the global model? You did not use the model from the 1st calculation.
hi, actually sub-model can be done manually using boundary condition (e.g displacement or rotation) from previous analysis. however CalculiX has advanced features for these specific task to do it automatically. it's use some methods known as mapping and it seems took result interpolation from nearest node of global models.
Is this program able to create multi point constraint? For example constraining line element to solid element
No, but you can use the Keyword Editor to define such constraints supported by CalculiX.
hi i've several models tested mixed element of beam, shell and solid, and it's possible using Tie constraint or Tied contact type
Looks good, is it possible to use this function with a shell global model and a solid sub model? I worry about mesh stiffness accuracy with coarse tet meshes.
Well, this might actually work but I would have to check it. Calculix internally transforms shell finite elements to volume finite elements and saves the results as solid. So the global result model .frd will contain 'usable' solid results.
@@MatejBorovinsek just another hints from my previous analysis work, yes it's possible connecting edge shell to face of solid element using tie contact. however i did not ever try using sub-model features.
One question, how come the submodel is deformed in opposit direction?
You are right. This was already noticed by the user 4P Ingeniería and was answered by me previously. I made a mistake preparing the video :)
With the software can I export the models to DIANA FEA?
I am not familiar with DIANA FEA, but the model in PrePoMax is exported in a .inp format of Abaqus. So if you can import .inp files then yes.
Dear Professor, i am interesting to learn about prepomax. But how do we create something new without import? Is it possible? If i use calculix for windows, how do i import ? Please i need your help
PrePoMax has no CAD features so the geometry must be prepared in some other software.
You can use e.g. FreeCAD to prepare the geometry for PrePoMax.