n5321 | 2025年6月15日 23:43

Tags: CAE

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I started my career doing FE modeling and analysis with ANSYS and NASTRAN. Sometimes I miss these days. Thinking about how to simplify a real world problem so far that it is solvable with the computational means available was always fun. Then pushing quads around for hours until the mesh was good had an almost meditative effect. But I don't feel overwhelmingly eager to learn a new software or language.

Much to my surprise, it seems there hasn't been much movement there. ANSYS still seems to be the leader for general simulation and multi-physics. NASTRAN still popular. Still no viable open-source solution.

The only new player seems to be COMSOL. Has anyone experience with it? Would it be worth a try for someone who knows ANSYS and NASTRAN well?




I've used ansys daily for over a decade, and the only movement is in how they name their license tiers. It's a slow muddy death march. Every year I'm fighting the software more and more, the sales men are clearly at the wheel.

They buy "vertical aligned" software, integrate it, then slowly let it die. They just announced they're killing off one of these next year, that they bought ten years ago, because they want to push a competitive product with 20% of the features.

I've been using nastran for half as long but it isn't much better. It's all sales.

I dabbed a bit in abaqus, that seems nice. Probably cause I just dabbed in it.

But here I'm just trying to do my work, and all these companies do is move capabilities around their license tiers and boil the frog as fast as they get away with.


I've gone Abaqus > Ansys > Abaqus/LS-DYNA over my career and hate Ansys with a fiery passion. It's the easiest one to run your first model in, but when you start applying it to real problems its a fully adversarial relationship. The fact you have to make a complete copy of the geometry/mesh to a new Workbench "block" to run a slightly different load case (and you can't read in an orphaned results files) is just horrible.

Abaqus is more difficult to get up to speed in, but its really nice from an advanced usability standpoint. They struggle due to cost though, it is hugely expensive and we've had to fight hard to keep it time and time again.

LS-Dyna is similar to Abaqus (though I'm not fully up in it yet), but we're all just waiting to see how Ansys ruins it, especially now that they got bought out by Synopsys.


I don't know how long ago you used ansys, and i definitely don't want to sell it, but you can share geometry/mesh between those "blocks" (by dragging blocks on top of each other), and you can read in result orphaned result files.


> Still no viable open-source solution.

For the more low-level stuff there's the FEniCS project[1], for solving PDEs using fairly straight forward Python code like this[2]. When I say fairly straight forward, I mean it follows the math pretty closely, it's not exactly high-school level stuff.

[1]: https://fenicsproject.org/

[2]: https://jsdokken.com/dolfinx-tutorial/chapter2/linearelastic...


Interesting. Please bear with me as this is going off 25 year old memories, but my memory is that the workflow for using FEA tools was: Model in some 3D modelling engineering tool (e.g. SolidWorks), ansys to run FEA, iterate if needed, prototype, iterate.

So to have anything useful, you need that entire pipeline? For hobbyists, I assume we need this stack. What are the popular modelling tools?


To get started with Fenics you can maybe use the FEATool GUI, which makes it easier to set up FEA models, and also export Python simulation scripts to learn or modify the Fenics syntax [1].

[1]: https://www.featool.com/tutorial/2017/06/16/Python-Multiphys...


Yeah not my domain so wouldn't really know. For FEniCS I know Gmsh[1] was used. There's some work[2][3] been done to integrate FEniCS with FreeCAD. It seems FreeCAD also supports[4] other FEM solvers.

But, I guess you get what you pay for in this space still.

[1]: https://gmsh.info/

[2]: https://github.com/qingfengxia/Cfd

[3]: https://github.com/qingfengxia/FenicsSolver

[3]: https://wiki.freecad.org/FEM_Solver


You can export other CAD meshes for use in it


> For hobbyists, I assume we need this stack.

Just curious what kind of hobby leads to a finite element analysis?


Electronics (when you start to care about EMI or antenna design), model airplanes (for aerodynamics), rocketry, machining (especially if you want to get into SPIF), robotics, 3-D printing (especially for topology optimization), basically anything that deals with designing solid structures in the physical world. Also, computer graphics, including video games.

Unfortunately the barrier to entry is too high for most hobbyists in these fields to use FEM right now.


There are some obvious downsides and exceptions to this sentiment, but on balance, I really appreciate how the expansive access to information via the internet has fostered this phenomenon: where an unremarkable fella with a dusty media studies degree, a well-equipped garage, and probably too much free time can engineer and construct robotic machines, implement/tweak machine vision mechanisms, microwave radio transceivers, nanometer-scale measurements using laser diodes and optical interferometry, deep-sky astrophotography, etc., etc.. Of course, with burgeoning curiosity and expanding access to surplus university science lab equipment, comes armchair experts and the potential for insufferability[0]. It’s crucial to maintain perspective and be mindful of just how little any one person (especially a person with a media studies degree) can possibly know.

[0] I’m pretty sure “insufferability” isn’t a real word. [Edit: don’t use an asterisk for footnotes.]


> comes armchair experts and the potential for insufferability

Hey, I resemble that remark! I'd be maybe a little less armchair with more surplus equipment access, but maybe no less insufferable.

By all accounts, though, a degree of insufferability is no bar to doing worthwhile work; Socrates, Galileo, Newton, Babbage, and Heaviside were all apparently quite insufferable, perhaps as much so as that homeless guy who yells at you about adrenochrome when you walk by his park encampment. (Don't fall into the trap of thinking it's an advantage, though.) Getting sidetracked by trivialities and delusions is a greater risk. Most people spend their whole lives on it.

As for how little any person can know, you can certainly know more than anyone who lived a century ago: more than Einstein, more than Edison, more than Noether, more than Tesla, more than Gauss. Any one of the hobbies you named will put you in contact with information they never had, and you can draw on a century or more of academic literature they didn't have, thanks to Libgen and Sci-Hub (and thus Bitcoin).

And it's easy to know more than an average doctorate holder; all you have to do is study, but not forget everything you study the way university students do, and not fall into traps like ancient aliens and the like. I mean, you can still do good work if you believe in ancient aliens (Newton and Tesla certainly believed dumber things) but probably not good archeological work.

Don't be discouraged by prejudice against autodidacts. Lagrange, Heaviside, and du Châtelet were autodidacts, and Ptolemy seems to have been as well. And they didn't even have Wikipedia or Debian! Nobody gets a Nobel for passing a lot of exams.


IMO, the mathematics underlying finite element methods and related subjects — finite element exterior calculus comes immediately to mind — are interesting enough to constitute a hobby in their own right.


FEniCs is mostly used by academic researchers, I used it for FEM modelling in magnetic for e.g. where the sorts of problems we wanted to solve you can’t do in a commercial package.


COMSOL's big advantage is it ties together a lot of different physics regimes together and makes it very easy to couple different physics together. Want to do coupled structures/fluid? Or coupled electromagnetism/mechanical? Its probably the easiest one to use.

Each individual physics regime is not particularly good on its own - there are far better mechanical, CFD, electromagnetism, etc solvers out there - but they're all made by different vendors and don't play nicely with each other.


> The only new player seems to be COMSOL

Ouch. I kind of know Comsol because it was already taught in my engineering school 15 years ago, so that it still counts as a “new entrant” really gives an idea of how slow the field evolves.


The COMSOL company was started in 1986....


It used to be called FEMLAB :)

But they changed to COMSOL because they didn't have the trademark in Japan and FEM also gave associations to the feminine gender.


I am hoping this open source FEM library will catch on : https://www.dealii.org/. The deal in deal.II stands for Differential Equation Analysis Library.

It's written in C++, makes heavy use of templates and been in development since 2000. It's not meant for solid mechanics or fluid mechanics specifically, but for FEM solutions of general PDEs.

The documentation is vast, the examples are numerous and the library interfaces with other libraries like Petsc, Trilinos etc. You can output results to a variety of formats.

I believe support for triangle and tetrahedral elements has been added only recently. In spite of this, one quirk of the library is that meshes are called "triangulations".


I've worked with COMSOL (I have a smaller amount of ANSYS experience to compare to). For the most part I preferred COMSOL's UI and workflow and leveraged a lot of COMSOL's scripting capabilities which was handy for a big but procedural geometry I had (I don't know ANSYS's capabilities for that). They of course largely do the same stuff. If you have easy access to COMSOL to try it out I'd recommend it just for the experience. I've found sometimes working with other tools make me recognize some capabilities or technique that hadn't clicked for me yet.


Once you have a mesh that's "good enough", you can use any number of numeric solvers. COMSOL has a very good mesher, and a competent geometry editor. It's scriptable, and their solvers are also very good.

There might be better programs for some problems, but COMSOL is quite nice.


OpenFOAM seems like an opensource option but I have found it rather impenetrable - there are some youtube videos and pdf tutorials, but they are quite dense and specific and doens't seem to cover the entire pipeline

Happy to hear if people have good resources!


Still no viable open-source solution.

Wait? What? NASTRAN was originally developed by NASA and open sourced over two decades ago. Is this commercial software built on top that is closed source?

I’m astonished ANSYS and NASTRAN are still the only players in town. I remember using NASTRAN 20 years ago for FE of structures while doing aero engineering. And even then NASTRAN was almost 40 years old and ancient.


There's a bunch of open source fem solvers e.g. Calculix, Code_Aster, OpenRadioss and probably a few unmaintained forks of (NASA) NASTRAN, but there's no multiphysics package I don't think.


These are at least capable of thermomechanical with fluid-structure coupling. Not all-physics but still multi. True that things with multi species diffusion or electromagnetics are missing, but maybe Elmer can fill the gap.


Abaqus is pretty big too. I've worked with both Ansys and Abaqus and I generally prefer the latter.


Abaqus is up there with Ansys aswell as others have mentioned.


As a recovering fe modeler, I understand completely.


I work in this field and it really is stagnant and dominated by high-priced Ansys/etc. For some reason silicon valley's open sourceness hasn't touched it. For open source, there's CalculiX which is full of bugs and Code Aster which everybody I've heard about it from say it's too confusing to use. CalculiX has Prepomax as a fairly new and popular pre/post.




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