PrePoMax & CalculiX - Shell features
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- เผยแพร่เมื่อ 24 ส.ค. 2024
- A new version of the free PrePoMax pre and post-processor for the CalculiX FEM solver adds the possibility to create shell compound parts, to display and flip shell face orientations and to split faces with internal edges.
![ฮักเทื่อสุดท้าย - บอย ศิริชัย [OFFICIAL MV]](http://i.ytimg.com/vi/-1PoPoQ-B-k/mqdefault.jpg)
Prepomax is impressive, congratulations. I'm very excited to use it. I am obtaining excellent results in non-linear simulations on top load bottles.
Thank you, I am very happy you like it. If you have any ideas how to improve it please join out forum.
This software is just incredibly good, the best of its kind. If I may suggest something, when it comes to potential new functionalities in the future, it would be great to have beam elements, 2D (plane stress/strain) and maybe axisymmetric models as well as thermal analyses implemented. I was also thinking about more types of materials (hyperelastic, creep, composites) but I assume that they can be easily defined via Calculix keyword editor.
Thank you Jakub. All of your wishes are already on the to-do list. They will be added in the future, but it might take a while to implement all of them. The features that are possible using a keyword editor have lower priority.
@@MatejBorovinsek regarding to-do list features: auto generate spring element to mimics *Foundation keywords in Abaqus are in the list and priority? this works like Surface traction already implemented, except using input as spring stiffness per unit areas to generated spring element along normal direction and assign calculated stiffness individually. it would be hard and cumbersome to manually edit, so many thanks.
That was not on the to-do list. But I added it now. It would have to be something like a soft BS or similar.
Very nice! I was wondering that which GUI programming did you use?
PrePoMax is developed using C# inside Visual Studio. A VTK library is used for 3D graphics.
Hi, first of all,congratulations for the program, very well done! A question : it is possible to hide the element thickness in post processor contour plot, in order to view only the shell mesh? thank you very much
At the moment this is not possible. The reason is that CalculiX expands shell finite elements into solid finite elements and then computes the solution. So the results are based on the solid elements contained in the results.
in addition to Matej B. comment, you could set the output to 2D under Field Output menu tree's. but you can not use both of 2D flat and 3D extruded at the same process in current versions. may in future PrePoMax versions can do mixing of both result views.
Hello. Great job, Thank you. I have a question for you. As you may know, in Abaqus software we can select the type of a part, for example, it could be a deformable or a discrete rigid. I want to know how I can define a part as discrete rigid in this software. Also, I am doing a compaction simulation via this software. The punch doesn't move downward when I assign a displacement to the reference point of the punch, but it moves once a displacement is defined on the top surface of the punch. Could you please tell me how I can define a discrete rigid part? and how can I assign a displacement to the RP?
You can add a rigid body using Constraints. For a more detailed answer please use our forum.
@@MatejBorovinsek Thank you so much for your reply. Indeed, I signed in for it, but my account has not been accepted yet.
Great pre processor. Is there anywhere I can see a workflow with a compound shell part with different shell sections around the structure?
No. But it should not be too hard to manage. You can assign sections to selection (in the current version the whole part), to the part and to the element set. For your purpose, instead of selection, choose the element set option. The appropriate element sets must be prepared in advance.
@@MatejBorovinsek Thanks - that worked!!
It is the best interface for FEM! I think that ANSYS and another software not so good, if to compare the ANSYS with this cool stuff! Prepomax best of the best!
I have some question for you, did you use the VTK and PyQT librery for visualization? It is wrote on Python?
Thank you. Indeed, I have used the VTK library. But I used it from a C# programing language using Visual Studio.
Do you plan to add an option to transform the results to user-defined coordinate system (cartesian, cylindrical or spherical) ?
Yes, there is already a topic about this in the to-do list.
hi. Great video。 Thank you. I want to know Is there any way to export stress fields from Prepomax to a .csv file. Something with the node data (x,y,z location) and the field value at the node.I add the keyword(example:*El print, ELSET=Element_Set-1 COORD, S ).But It doesn't run.
Please use our forum for specific questions: prepomax.discourse.group/. However, in general, it is not possible to export data from PrePoMax directly. You can use the .dat file produced by the CalculiX FEM solver to get such results, but the file format can not be changed.
@@MatejBorovinsek ok，I got it .Thank you very match.
cadê o áudio?
Hello,
Sometimes I have an issue with shell components. I have red edges but on free edges or on edges in contact with curved surfaces. Is there a way to fix it on PrePoMax please ?
Red edges represent an invalid topology of the geometry. A shell face must not contain any internal free edges that are not loops (holes).
How can i devide one shell model (1 compound) into parts made of different thickness? I have tried to make several compounds and glue then together with tie constrain but it does not work. Also if i try to do it as 1 compound the shell section comand automaticly picks the whole compound - even when i pick one surface of the model. Grettings for Poland
You can assign sections to selection (in the current version the whole part), to the part and to the element set. For your purpose, instead of selection, choose the element set option. The appropriate element sets must be prepared in advance.
@@MatejBorovinsek Thank you so much! It worked - absolutly a fan of your program.
hi. What program do you recommend to prepare a shell drawing? thx and thx 4 very good software!
Well, probably FreeCAD is the best option.
@@MatejBorovinsek ok, thx. I normally use T-flex cad.. so lets do it by freecad ;)
Hi friend. install it. but when I want to open my step it tells me that "the directory does not exist" and does not open anything finally ...
This is probably a problem with the directory access. Do not put the PrePoMAx in a system folder, like Program Files. To test this, put it directly on the c:\PrePoMax or d:\PrePoMax.
@@MatejBorovinsek Hi Matej. I was finally able to install. Thank you. I wanted to ask you what we see in this section: / result field / output / error
@@rfuentelzar It is an estimation of the error for all computed fields due to the discretization (mesh size, element type) of the model. For a detailed description please see the CalculiX documentation.
Hi Matej, it is possible to create a shell face to face contact in prepomax?
Yes, this is possible.
I get an error message "The selection type and the section region are not compatible" when I try to create a shell section- do you know why that might be? Also awesome work with this!
This means that you have a solid geometry and you try to assign a shell section to it or vice versa.
Здорова!
Есть ли возможность импортировать твердотельные модели из Autocad?
Планируете ли Вы сделать "справку" по программе?
Заранее благодарен за ответы
Since I had to translate your question I hope I got it right. If you can save the 3D model in Autocad in .step format it is possible to import it into PrePoMax. The documentation or help will probably be added later.
@@MatejBorovinsek Спасибо. Вы правильно поняли. К сожалению, в Autocad нельзя создать файл *.step.
Будем ждать руководство пользователя. Программа очень хорошая!
hi,
i try working with STL files for shell element, however it seems not working goods as another file format supported.
* preview edge mesh can not be displayed
* only triangular mesh, quad dominates is not.
* quadratic mesh is not generates even it's already defined.
* selection based on geometry for each edge parts (only for a whole edge boundaries)
is it possible to improve these limitation or can not, due to the lack of STL format itself?
and for general problem limitations,
* edge pressures for normal directions is not provided (resultants of distribution concentrates force only)
* change element types in GUI menu is limited (plane stress, strain, etc are not supported) need to exit and switch to another input editor & post-processor
* layered shell element (composite) to improves analysis results within GUI's (optional, since it can be simple overwrites using Edit Keyword features without leaving PrePoMax environments)
am i miss something i did not find using PrePomax here? if it right things as is as described above, hope all of these are in to-do list of improvement for next future release.
best,
syont
Yes, stl and shells are a bit tricky. The problem is that Netgen which is used doesn't support meshing of the "open" or shell geometry. That is why I added an additional tool. A tool that re-meshes the stl triangulation. In this way, I can create meshes for most parts but it has some limitation. No preview of edge mesh is possible and no quads are possible. The only real solution would be to change how the Netgen works which would take a lot of time.
The edge selection of entire edges is another problem but this one can be solved more easily.
Edge pressure is not supported yet but will probably be added in the future.
The 2D problems are not supported yet. So only 3D shell elements are supported in this version. 2D support will be added in the future.
Layered shell elements - I would be glad if you could send me an example file with composite shells to test it and to find out what is missing.
@@MatejBorovinsek thank you for reading & respects my listed comments, wish you best.
n.b. there's no problems in layered shell element. only thinking it will be nice doing inside GUI's, even for simple ones for isotropic.
@@MatejBorovinsek hi, is there posibilities to merge nearby coincident nodes? for some reason my "brep" CAD files always treat as separated surface when imported and it's dissapear/lost, fail to merge by compound part features.
@@syont No, it is not possible. But since it is a useful feature it is on the to-do list. The problem with separate parts is that the mesh is not necessary coincident all along the edges. So merging will not work for all nodes. How do you prepare the .brep files? Salome?
@@MatejBorovinsek thanks for answer, yes right i'm using Salome a lite versions (CAD Builder), in case of step files there's no problem to merge compound part (surface) inside PrePoMax. trouble are in drawing units, always multiple by one thousand due to default metre units embeded in file informations. tried several methods still did not succeed, it seems required to drawn in metre units or do scaling. only brep file format work as expected.