Hello everyone, this is my first post and I wanted show the wingbox I was able to model using the M3D program.

Last weekend I decided to try M3D out by myself for the first time. I would like it to become my main pre and pro-processor for Mystran and since efforts are being made to achieve this goal for the community, I thought it would be useful for other users to share my experience with it like the most useful tools, some pitfalls and showing the progress in general.

My only input was the set of points shaping an airfoil from the "airofoil.txt" archive located in the Examples folder. From there, with a bit of pacience and after playing around with literally every button and functionality I found, I was able to create the following model:
               

Things to note:
Although M3D currently lacks some automatic quad paver mesh for quads (it only has the advanced front tria mesh) I found it has huge potential for manual meshing (this is good news for some of us who like to have full control when meshing), specially regarding the 1D and 2D elements (Good for aero ): My 4 most used commands here were:

    -sweep nodes to beams (to create and extend the stringers and spar caps spanwise) --> located in the menu create ---> FEM tools
    -sweep nodes to quads (to create and extend the panels and spar webs spanwise) --> located in the menu create ---> FEM tools
    -copy selected objects (acts like an overpowered reflect, ideal for placing multiple rib stations) --> available as a symbol by default
    -create quad elements from set of nodes (to create an organized cquad mesh, specially useful with curved surfaces) --> available as a symbol by default

With these four in action, the most efficient workflow I found was create first the 2D mesh of the rib that will serve as a "footprint", then build the rest of components like spar webs and caps, panel skins and stringers by extruding directly the nodes you want in CBEAM and CQUAD elements (you can specify the total length of the extrusion and the number of elements per length). This is great since you dont need an intermediate element to extrude, you just select the nodes to locate where you want to extrude directly.

The "create quad elements from sets of nodes" is one of the tools I have used the most also, it is the closest to an automatic quad meshing when the surface is not straight, very useful for curved surfaces like the ribs for example.
The "copy selected objects" command copies and translates the number of times you input an object, in this case the Rib mesh spanwise, it is like a powerful version of reflect.

After all of these action have been done, keep in mind the nodes are duplicated (between spar webs and panels, also with CBAR nodes) so in order to merge them you have to use the merge coincident nodes. I saw that it will actually merge the nodal position of each element to the one with higher or lower node label (depends on what you choose) but it does NOT merge nodes (in the sense of keeping one and deleting the other), you have to delete them after with the delete button by selecting all the model (DEL key also works for deleting the free nodes within your selection). This was tricky because being used to hypermesh each time I merge nodes, the merged nodes are deleted and I dont have to take care of them anymore, here it is a 2 steps process: Merge "nodal positions" of very close elements and then delete the free nodes.

Things I found it would be helpful to improve:

    -Preserve same filter used in repeat last command action.
    -Add mask functionality to the group management menu, it only has the ability to isolate the current group, but what if I just want to hide some particular locations of my model.
    -How to tell there are 1D elements in a 2D mesh (the quads and tria edges hide the 1D elements) when there is no property applied yet, ease the 1D element visualization.
    -Advancing front meshing does not respect nodes already existing in the model (creates connectivity problems, can't join detailed meshes with the one being created)
    -Translate option is either you know the module and direction (by key) or you specify both by the relative position of 2 objects (for example between 2 selected nodes)
     Here it would be incredibly useful if both functionalities were fusioned: You input the distance module you want, and then you specify the direction by picking 2 nodes or other set of         object that follows the direction you wish.
    -During the merge nodes task, maybe add a hint reminding the user that nodes are still there and they need to be deleted.

I find M3D a promising candidate for Mystran, once you start understanding how the program works and what it expects from you as inputs, it really feels nice and smooth, it is like a compilation of some of the most used tools in comercial pre-processors.

My intention is to continue with the model by applying properties, constraints and some typical load cases and see how it goes. Once it is finished, I will try a more complex model of a wing with some wing warping, sweepback angle and wingtips, I even plan to model the engine as a concentrated mass but well... the idea is to challenge M3D with more complex constructions.

Please do not hesitate to comment and share how you would have done something in a different way, at the end of the day I am learning the program and the more we are trying it the better for everyone.

Cheers!

First Watch - Is M3D Right For You?
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https://www.espcomposites.com/1_M3D_Preliminary.mp4


Tutorial Series (Step-by-Step)
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https://www.mystran.com/forums/showthread.php?tid=115
  

Official User Guide
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http://www.m3dfea.com/user-guide.html


YouTube Videos
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Beam Tutorial
https://www.youtube.com/watch?v=CxOtORha4mY

Constructing a Gear
https://www.youtube.com/watch?v=RIh1wPpovVw

Simple Floor Slab
https://www.youtube.com/watch?v=cS96mYU0Iuc

Basic Model
https://www.youtube.com/watch?v=vdb0Wticp3k

Mesh Beam Cross Section
https://www.youtube.com/watch?v=-pP7Uz76Gj4

Other
-----------------------
WingBox
https://www.espcomposites.com/M3D_Wingbox.mp4

Informal Tutorials..more information to come soon. This is just to get things started:

https://www.espcomposites.com/1_M3D_Preliminary.mp4

https://www.espcomposites.com/2_M3D_Intro_1.mp4

https://www.espcomposites.com/3_M3D_Intro_2.mp4

https://www.espcomposites.com/4_M3D_Solid_Beam_1.mp4

https://www.espcomposites.com/5_M3D_Solid_Beam_2.mp4

https://www.espcomposites.com/6_M3D_Plate_With_Hole.mp4

https://www.espcomposites.com/7_M3D_Plat..._Holes.mp4

https://www.espcomposites.com/8_M3D_Truss_Script.mp4

https://www.espcomposites.com/9_M3D_Mate...erties.mp4

More Info Coming Soon

Informal Tutorials..more information to come soon. This is just to get things started:

https://www.espcomposites.com/1_M3D_Preliminary.mp4

https://www.espcomposites.com/2_M3D_Intro_1.mp4

https://www.espcomposites.com/3_M3D_Intro_2.mp4

https://www.espcomposites.com/4_M3D_Solid_Beam_1.mp4

https://www.espcomposites.com/5_M3D_Solid_Beam_2.mp4

https://www.espcomposites.com/6_M3D_Plate_With_Hole.mp4

https://www.espcomposites.com/7_M3D_Plat..._Holes.mp4

https://www.espcomposites.com/8_M3D_Truss_Script.mp4

https://www.espcomposites.com/9_M3D_Mate...erties.mp4

This is an informal history of history of MYSTRAN and where the project is going. I will also be posting a series of videos that explain how to use M3DFEA. Have a look at this video so get a better understanding of our goals and direction.

https://www.espcomposites.com/MYSTRAN_Overview_2025.mp4

https://www.structuralfea.com

1D Elements© is a user friendly finite element pre/post processor that uses beam, rod, and spring elements in 2D space. It is Excel based and uses VBA (Visual Basic for Applications) to allow for advanced capability. 1D Elements is compatible with the included free MYSTRAN solver (similar to Nastran) or the MSC Nastran solver. This combination is a standard approach to finite element analysis (pre/post processer and a solver).

I am currently evaluating Mystran and am particularly interested in understanding whether it offers an "inertial relief" feature similar to that in Nastran. I have cases with unrestrained structures under applied loads. Could you let me know if Mystran supports this functionality or if there are alternative methods to achieve a similar effect?

I've been trying to modify the Mystran writer in FreeCAD to write composite cases with orthotropic material and composite laminate cards. I've been referring to the MSC Nastran "Quick" Reference Guide (all 3417 pages of it!). I'm calculating orientation angle relative to the element reference direction as described in the guide. I think I now have this working. I'll share the code when I get it less hacky, eventually I want to read a ply book from a spreadsheet, at the moment I'm hard coding everything just to test it.

It creates a .bdf file which does solve (hooray!), however the results aren't right (boohoo!). I've attached a very simple test file (.txt extension added to allow it's upload to this forum, remove to use). You can see from the PCOMP card (line 41 onwards) that I have the ply orientations all set to 45 degrees. Since this is unbalanced (there are no -45 plies) then there should be strong bend-twist coupling, so the deformed shape should show some twist, but it doesn't. Also if you manually change the values of the plies to all 0 or all 90 and re run then there is nothing like enough difference in the deflection. The difference in modulus between the two directions is about 20x, so the deflection should be an order of magnitude lower for the 0 degree case than the 90 degree case. However they're coming out very similar.

Something clearly isn't being applied correctly. I'm not sure if this is the element orientations, the PCOMP card or the MAT8 card. Any ideas, I'm a bit stumped?

Attached Files

  FEMMeshGmsh.bdf.txt (Size: 1.74 KB / Downloads: 0)

pyNastran has an Abaqus to Nastran converter (so it works with CalculiX and MYSTRAN as well). In the event that you don't want to install pyNastran and just want something simple and quick...see this link (courtesy of Bruno).

ABAQUS to Nastran converter:
https://bor.gs/inp2nas/