CAE results interpretation

About the development of the FEM module/workbench.

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heda
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Joined: Sat Dec 12, 2015 5:49 pm

Re: CAE results interpretation

Post by heda »

taifun wrote: Thu Oct 14, 2021 11:26 am this structure
looks like something that is not going to be used in the basement where noone will bother if it is safe or not.

everyone has listed theory books, but is it not so that if you intend to use something, either commercially or around people that are not only yourself in miniscale at home - there are typically regulations around that and those regulations/guidelines basically tell you what to study and how to secure a sound structure for the intended use. Often these are giving you the way to calculate, and also have evaluation criteras to be fulfilled, sometimes also on how "stressed" a material is allowed to be, etc.

just saying....
aerospaceweeb
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Re: CAE results interpretation

Post by aerospaceweeb »

I've used many books about FEA but my favorite ones when it comes to theory are those written by Bathe ("Finite Element Procedures") and Cook ("Concepts and Applications of Finite Element Analysis", I don't know the other one you've mentioned). I would recommend Crisfield ("Non-linear Finite Element Analysis of Solids and Structures") if you want to study nonlinearities and Wriggers ("Computational Contact Mechanics") in case you want to focus on contact modeling.

Personally, I don't like "The Finite Element Method" trilogy written by Zienkiewicz and my colleagues share this point of view. Those books are hard to read and discuss rather exotic topics.

There are also two books about practical aspects of FEA worth recommending: "Building Better Products with Finite Element Analysis" by Adams and "Practical Finite Element Analysis for Mechanical Engineers" by Madier. The first one is a bit old (written in late 90s) but still relevant. The other one was written last year and is a very good start.
[/quote]

Oh MAN dude I've been stuck on the Zienkiewicz trilogy for like two months now and one of my two main mentors at work, who GAVE them to me when he retired, still asks me what I think of them and he just doesn't get my frustration. I've never actually read Crisfield, but I have several of his papers in binders that I inherited that I have embarassingly never really used... despite the fact that I implemented his buckling formulations for a snap-through code in matlab a fear years ago haha.

That book on contact modeling is going to be a gamechanger for me. I finally got access to a hypermesh at work as of maybe a year ago and I've been trying to get better at contact modeling. Thank you for this list. That new one looks excellent.
taifun
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Joined: Thu Oct 14, 2021 11:00 am

Re: CAE results interpretation

Post by taifun »

I finally managed to create a shell from the solid i previously used hoping to get better results. It took less time to create the mesh and to compute the results but i still couldn't get lower that 15mm element size for the mesh. This time i am also attaching the model.
Attachments
f2_shell_adv.FCStd
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13.jpg (51.77 KiB) Viewed 3224 times
12.JPG
12.JPG (161.95 KiB) Viewed 3224 times
cad1234
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Re: CAE results interpretation

Post by cad1234 »

OT
Just downloaded e-book
“Practical Finite Element Analysis” (price: 17 $, approx 15 EUR with paypal), -> one recommended book in this thread,
from here:

https://www.fea-academy.com/index.php/book-store

Table of contents
https://www.fea-academy.com/pdf/PFEA-Ta ... ntents.pdf

Great book about practical use of FEM from my point of view..
Have been looking for a book like this for so long!
Many thanks for the recommendation!!
aerospaceweeb
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Joined: Fri Apr 09, 2021 3:26 am

Re: CAE results interpretation

Post by aerospaceweeb »

I just purchased it as well.

As luck would have it, It is based around the most popular solver on earth, Nastran!

If you'd like to follow along, here's a page for a solver that's largely similar to it.

https://github.com/dr-bill-c/MYSTRAN

FreeCAD ought be supporting it better soon.
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johnwang
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Re: CAE results interpretation

Post by johnwang »

cad1234 wrote: Tue Oct 19, 2021 1:36 pm “Practical Finite Element Analysis”
I am trying to solve its demo cases with Nastran95/Mystran.
hfc series CAE workbenches for FreeCAD (hfcNastran95, hfcMystran, hfcFrame3DD, hfcSU2 and more)
cad1234
Posts: 331
Joined: Fri Dec 28, 2018 11:11 am

Re: CAE results interpretation

Post by cad1234 »

johnwang wrote: Sat Oct 23, 2021 3:14 am I am trying to solve its demo cases with Nastran95/Mystran.
Hi John
would be fantastic if that were possible!!
for everyone who is interested, he are the links to the files
https://www.fea-academy.com/index.php/resources
twangrt
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Joined: Sun Apr 28, 2019 6:34 pm

Re: CAE results interpretation

Post by twangrt »

NewJoker wrote: Mon Oct 18, 2021 6:17 pm There are also two books about practical aspects of FEA worth recommending: "Building Better Products with Finite Element Analysis" by Adams and "Practical Finite Element Analysis for Mechanical Engineers" by Madier. The first one is a bit old (written in late 90s) but still relevant. The other one was written last year and is a very good start.
Thanks for the recommendation. 'Practical Finite Element Analysis for Mechanical Engineers' seems like a very comprehensive book for 17 dollars, as mentioned before by others. The book has a very good practical viewpoint. Even as an e-book, with a lot of 'space', pictures and the fact that you're only able to read it in a specific pdf-reader, the book seems worth the money.
aerospaceweeb
Posts: 118
Joined: Fri Apr 09, 2021 3:26 am

Re: CAE results interpretation

Post by aerospaceweeb »

johnwang wrote: Sat Oct 23, 2021 3:14 am I am trying to solve its demo cases with Nastran95/Mystran.
I didn't know this was where you were getting test problems.

I'd be happy to help you rough these out in mystran. Maybe discuss on the discord, I'll see you there.
thschrader
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Location: Germany

Re: CAE results interpretation

Post by thschrader »

@taifun:
You can reduce the structure to a 2D-problem using beam elements in FC.
Convert L-shapes to an equivalent quadratic shape (area), this gives the same stiffness/stresses.
Once you have the stresses/forces, check local buckling of beams and the connections.
Then the anchoring to the foundation and the foundation itself.
f2_shell_adv_ths.FCStd
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calculation.JPG
calculation.JPG (136.86 KiB) Viewed 2771 times
Done with:
OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.25645 (Git)
Build type: Release
Branch: master
Hash: 37d9757399b4c2ec30318eb88d7cd7c508246345
Python version: 3.8.6+
Qt version: 5.15.2
Coin version: 4.0.1
OCC version: 7.5.0
Locale: German/Germany (de_DE)
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