FEA Program

[rickylee]

I am looking for a basic FEA program to use with AutoCAD 2d drawings. Typical use would be pressurized fittings and basic machine components. Does anyone have any suggestions that I should look at? How about AutoFEA JLAnalyzer 9.0?

Thanks, Rick

 

[johnhors]

Rick

You could look at

http://www.dermotmonaghan.com

, he has a section on freeware FEA and a comprehensive section on commercial FEA, otherwise there are several low cost (but very capable) packages that you can consider eg. Femdesigner , Strand7 , Roshaz and so on.

 

[GBor]

Rick,

There is an FEA Forum (Forum 727) and all of us will have our opinions. By "basic machine components", will they still be 2-D axisymmetric, or will you need 3-D? Will you just do linear stress due to pressure in the fittings, or will you also do kinematics for any operating mechanisms? Will you need hyper-elastic materials for any seals or are they mechanical seals? And, perhaps most importantly, if you have the FEA capability, will you broaden your use of it?

Some questions to ask of your FEA package: Does it do what I want? Am I paying for functionality that I won't use? Does the software company offer training? Do they have sufficient tech support so that I don't "get the run-around" when I call? Is the documentation understandable and thorough? Is the user interface easy to deal with?

When we talk about FEA packages, most people are really referring to the pre- and post-processors. Few geeks (like me) really care what's happening "inside the black box". So long as you can perform hand calculations on some basic models and get back results that match from your FEA, you can have some confidence that it will work, so the question is how easy is it to build the model, can I perform checks that give me sufficient confidence in the results, and do I understand what my post-processor is giving me (this is particularly important as some processors give "smoothed" results and others give "absolute" results...good post-processors will give both!).

I can ramble for hours on this subject, so I will leave you with these comments and the thought that you may want to try the forum I mentioned above.

Garland

Garland E. Borowski, PE

 

[ctopher]

Can FEA be done on a 2D dwg?? I have never seen/heard of it.

Chris
Sr. Mechanical Designer, CAD
SolidWorks 05 SP1.1 / PDMWorks 05
ctopher's home site

 

[GBor]

You can do 2-D axisymmetric, plane stress, or plane strain. Your problems have to fit into one of these three limiting cases.

Garland E. Borowski, PE

 

[johnhors]

ctopher

Not everyone works in 3D, there are still significant numbers of 2D drawings being made, which can provide geometry for 2D FEA, i.e. plane stress/strain and axisymmetric FE models. In fact a skilled/proficient FE analyst should always try to simplify their models by taking advantage of plains of symmetry and EVEN reducing a 3D model to 2D if it is valid.

 

[johnhors]

Sorry, planes of symmetry not plains!

 

[ctopher]

Johnhors, I know, thank you.
I just never experienced FEA from 2D.
I have always used 3D and all of our customers require 3D FEA.

Chris
Sr. Mechanical Designer, CAD
SolidWorks 05 SP1.1 / PDMWorks 05
ctopher's home site

 

[corus]

JL analyser lets you open iges files etc. and is ok for very simple problems. For pressurised components such as vessels you would typically use 2D axisymmetric geometry, so it'd be ok, but limited. Try the free version of JL Analyser to see if you can cope with it.

corus

 

[GregLocock]

Z88 is free, fast and powerful, if you just want static analysis. It also has an automeshing ability that can be driven from Autocad.

That's the end of the sales pitch.

http://z88.uni-bayreuth.de/

However, I would say that it is not especially easy to learn, and the aforesaid ($10 word) meshing ability looks like a nightmare.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[rickylee]

Thanks everyone for the input, I am following up on many of your comments.

I am interested in further feedback on JL Analyser and Strand 7.

Thanks, Rick

 

[jhardy1]

rickylee,

I have been a long-term Strand7 user, and can highly recommend it as a mid-range FEA system. You can download a free demo (limited to 20 beams, or 100 plate/shell or solid elements, no save capability, but otherwise fully functional) from

http://www.strand7.com.au.

The demo will allow you to import and auto-mesh 2D and 3D models; however, you will only be able to solve and post-process your model if it remains within the node / element limit. However, you can still play with the CAD import and auto-mesh capability on larger, more complex models.

If your primary interest is in importing a 2D CAD model, and running axi-symmetric analysis, the demo is probably well worth a look, because you can probably create some reasonably detailed axi-symmetric models within the limit of 100 4-node or 8-node quad elements.

The user interface is excellent, and the feature list is excellent for low to mid price software. You get access to linear and non-linear static and transient solvers, thermal solver, etc, all in the base package (and all in the demo, too.)

Note that while it is markedly cheaper than most of the better known codes (Nastran, Algor, Cosmos, etc), it still costs several thousand dollars, so you need to think about what features you need, and what your budget is. Also, you should note that the CAD import and auto-mesh tool is an optional extra, not part of the base package (although it is in the free demo).

Hope this helps!

 

[jhardy1]

Sorry

http://www.strand7.com

 

[GregLocock]

You might want to look at Cadre Lite. I did last night, the freeware version supports a reasonably useful 1500 nodes and it runs fairly quickly.

google for it

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[jhardy1]

Cadre Lite is a fine program, but note that it only has beam elements (no plate / shell / solid elements), so it is generally only suitable for 2D and 3D skeletal frame and truss type problems.

 

[GregLocock]

Damn, I missed that. Thanks Julian.


Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.