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Eighty Years of the Finite Element Method (2022)

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Re: Eighty Years of the Finite Element Method (2022)

#21

Post by angry_moose »

navane wrote: post #13
weinzierl wrote: post #3

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 sur…

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…

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.

Re: Eighty Years of the Finite Element Method (2022)

#22

Post by antegamisou »

sashank_1509 wrote: post #10

My hot take is that, FEM is best used as unit testing of Machine Design, not a guide towards design that it’s often used as. The greatest mechanical engineer I know, once designed an entire mechanical wrist arm with five fingers, actuations, lots of parts and flexible finger tendon. He never used FEM at any part of his design. He instead did it in the old fashioned, design and fab a simple prototype, get a feel for i…

Good luck designing crash resilient structures without simulating it on FEM based software though.

Re: Eighty Years of the Finite Element Method (2022)

#23

Post by catgary »

angry_moose wrote: post #15

I've been a full-time FEM Analyst for 15 years now. It's generally a nice article, though in my opinion paints a far rosier picture of the last couple decades than is warranted. Actual, practical use of FEM has been stagnate for quite some time. There have been some nice stability improvements to the numerical algorithms that make highly nonlinear problems a little easier; solvers are more optimized; and hardware is…

I kind of thought Neural Operators were slotting into the some problem domains where FEM is used (based on recent work in weather modelling, cloth modelling, etc) and thought there was some sort of FEM -> NO lineage. Did I completely misunderstand that whole thing?

Re: Eighty Years of the Finite Element Method (2022)

#24

Post by angry_moose »

catgary wrote: post #23
angry_moose wrote: post #15

I've been a full-time FEM Analyst for 15 years now. It's generally a nice article, though in my opinion paints a far rosier picture of the last couple decades than is warranted. Actual, practical use of FEM has been stagnate for quite some time. There have been some nice stability improvements to the numerical algorithms that make highly nonlinear problems a little easier; solvers are more optimized; and hardware is…

I kind of thought Neural Operators were slotting into the some problem domains where FEM is used (based on recent work in weather modelling, cloth modelling, etc) and thought there was some sort of FEM -> NO lineage. Did I completely misunderstand that whole thing?

Those are definitely up next in the flashy-new-thing pipeline and I'm not that up to speed on them yet.

Another group within my company is evaluating them right now and the early results seems to be "not very accurate, but directionally correct and very fast" so there may be some value in non-FEM experts using them to quickly tell if A or B is a better design; but will still need a more proper analysis in more accurate tools.

It's still early though and we're just starting to see the first non-research solvers hitting the market.

Re: Eighty Years of the Finite Element Method (2022)

#25

Post by angry_moose »

sashank_1509 wrote: post #10

My hot take is that, FEM is best used as unit testing of Machine Design, not a guide towards design that it’s often used as. The greatest mechanical engineer I know, once designed an entire mechanical wrist arm with five fingers, actuations, lots of parts and flexible finger tendon. He never used FEM at any part of his design. He instead did it in the old fashioned, design and fab a simple prototype, get a feel for i…

To be fair, FEM is not the right tool for mechanical linkage design (if anything, you'd use rigid body dynamics).

FEM is the tool you'd use to tell when and where the mechanical linkage assembly will break.

Re: Eighty Years of the Finite Element Method (2022)

#26

Post by akomtu »

angry_moose wrote: post #15

I've been a full-time FEM Analyst for 15 years now. It's generally a nice article, though in my opinion paints a far rosier picture of the last couple decades than is warranted. Actual, practical use of FEM has been stagnate for quite some time. There have been some nice stability improvements to the numerical algorithms that make highly nonlinear problems a little easier; solvers are more optimized; and hardware is…

Could you write a blogpost-style article on how to model the shallow water wave equation on a sphere? The article would start with the simplest possible method, something that could be implemented in short C program, and would continue with a progressively more accurate and complex methods.

Re: Eighty Years of the Finite Element Method (2022)

#27

Post by littlestymaar »

weinzierl wrote: post #3

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 sur…

> 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.

Re: Eighty Years of the Finite Element Method (2022)

#28

Post by amelius »

catgary wrote: post #23
angry_moose wrote: post #15

I've been a full-time FEM Analyst for 15 years now. It's generally a nice article, though in my opinion paints a far rosier picture of the last couple decades than is warranted. Actual, practical use of FEM has been stagnate for quite some time. There have been some nice stability improvements to the numerical algorithms that make highly nonlinear problems a little easier; solvers are more optimized; and hardware is…

I kind of thought Neural Operators were slotting into the some problem domains where FEM is used (based on recent work in weather modelling, cloth modelling, etc) and thought there was some sort of FEM -> NO lineage. Did I completely misunderstand that whole thing?

I was under the impression that the linear systems that come out of FEM methods are in some cases being solved by neural networks (or partially, e.g. as a preconditioner in an iterative scheme), but I don't know the details.

Re: Eighty Years of the Finite Element Method (2022)

#29

Post by amelius »

sashank_1509 wrote: post #10

My hot take is that, FEM is best used as unit testing of Machine Design, not a guide towards design that it’s often used as. The greatest mechanical engineer I know, once designed an entire mechanical wrist arm with five fingers, actuations, lots of parts and flexible finger tendon. He never used FEM at any part of his design. He instead did it in the old fashioned, design and fab a simple prototype, get a feel for i…

If he were designing a bridge, however ...

Re: Eighty Years of the Finite Element Method (2022)

#30

Post by magicalhippo »

lll-o-lll wrote: post #19
magicalhippo wrote: post #6

Earlier quoted context omitted.

> 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?

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

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