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Old 4th May 2005, 12:09 AM   #1
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Default FEMM needed

I have been searching for a free FEMM simulation program to download, any recommendations?? Thank`s

Best regards,
Peter
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Old 4th May 2005, 12:38 AM   #2
JohnL is offline JohnL  United States
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I can't speak for the accuracy of the algorhythms, but it's freeware and the learning curve isn't too bad.

FEMM 3.4
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Old 4th May 2005, 01:58 AM   #3
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Hi JohnL.

Thanks a lot

This is great, i just hope i will manage to learn to use this program
I`ve got this strange feeling that it will be early in the morning when i go to bed

Best regards,
Peter
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Old 4th May 2005, 02:58 AM   #4
JohnL is offline JohnL  United States
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He's got a speaker motor in his examples area on the website, that's where I started. I'm just using it for some simple magnetic simulations, it took me a couple of days playing with it. I guess you could always read the manual, but that takes the fun out of it.
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Old 4th May 2005, 10:14 AM   #5
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Anyone know of something good for aoustic simulations (horn speakers in particular)? neo acoustics do some nice BEM software, but for a student that is just silly money.
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Old 5th May 2005, 01:29 AM   #6
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Matlab w/ PDE toolbox - used to be about $160 for the student edition. It's not really built in functionality to solve acoustics problems, although they do give an example of sorts... It would also be pretty difficult to do any kind of fully coupled model. It's basically useful for looking at wave propagation given a unit input. You can also predict polar patterns, etc. Check out my webpage for some stuff I've done with it.

I think someone here was also developing stand-alone code to do the same sort of thing, so you might try doing a search.
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Old 5th May 2005, 01:54 AM   #7
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Does anyone who actually knows what they're doing have the inclination to look at these packages and comment:

gmsh - the modeller/front end http://geuz.org/gmsh/

GetDP - the solver http://geuz.org/getdp/

No acoustics examples included, but it looks capable of handling it.
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Old 7th May 2005, 04:46 AM   #8
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This probably isn't particularly useful to anyone, but I use NASTRAN at work for structural modeling. It's far from free. There's also an acoustics solver bundled in with that. I've used that some to model my room. Calculating room modes was a piece of cake. Anything else got a bit more challenging. I did some frequency response runs and eventually got some reasonable looking results. You mesh the air. You can define acoustic absorber elements with frequency dependent absorbtion (technically acoustic impedance). For sources you can define an acoustic source or apply an enforced pressure.

I have a model of the LAB horn built, but haven't got anything to successfully run with it.

After sitting at a computer working with FEM (for a living) for 50+ hours a week, I don't have a huge motivation to sit there even longer in my time off to do more.

I'm sure I'll do some more with it sometime in the future. I want to do some sound absorber modeling (rigid fiberglass stuff) before spending money on some.

I posted a bit before.
link to batdorf rambling


- Robert
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