Anyone know how to use the FEM analysis tools in FreeCAD?

Learned a little more about this. One can mesh multiple zones at a higher density if needed. Was able to mesh at a 50um max cell size in the high stress region. I can see why tight radius is so bad for high pressure vessels, the stresses go way up. Like 1.3GPa in a 0.4mm radius, for a vessel pressurized to 75 MPa. UTS for 2024T3 is about 487 MPa, give or take. I could reduce the cell size further to see if the stress is convergent, but may run out of memory in my computer, it's getting close to the edge.
 
WobblyHand said:
Learned a little more about this. One can mesh multiple zones at a higher density if needed. Was able to mesh at a 50um max cell size in the high stress region. I can see why tight radius is so bad for high pressure vessels, the stresses go way up. Like 1.3GPa in a 0.4mm radius, for a vessel pressurized to 75 MPa. UTS for 2024T3 is about 487 MPa, give or take. I could reduce the cell size further to see if the stress is convergent, but may run out of memory in my computer, it's getting close to the edge.
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Computer limitations? That is why we run Aliens 12th gen I9, 64GB RAM, 16GB dedicated Video 3080 NVidia, it is a monster laptop....
 
I could add RAM to my laptop, it can take up to 64GB. Not sure I want to do that with this one. It has some kind of hardware error when using USB. The computer just freezes for a couple minutes and simply turns off the power. Most annoying. When I can find a decent deal, I will replace it. The logs show nothing, been frustrating to track down. USB memory works fine, but other USB stuff like Arduino programming randomly causes these shutdowns.
 
WobblyHand said:
I could add RAM to my laptop, it can take up to 64GB. Not sure I want to do that with this one. It has some kind of hardware error when using USB. The computer just freezes for a couple minutes and simply turns off the power. Most annoying. When I can find a decent deal, I will replace it. The logs show nothing, been frustrating to track down. USB memory works fine, but other USB stuff like Arduino programming randomly causes these shutdown
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Not certain what the USB issue is, it could be a number of things. I like the Aliens (Very high end Dell) and I bought myself one Alienware x17 R2, Not cheap but worth every dime, on my personal I got the 34XX x 24XX res monitor and the mechanical Keyboard.... I deal with files and file sets which bump 500Gb at work and my tinkering at the house doing such things as you are playing with. , there is no substitution for horse power.... :chunky:

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It's probably the fact that this computer is a pandemic laptop, ie, not quite made right. Or they used 3/4 of the correct amount of solder paste, or something stupid like that. It's not a CPU thermal thing. Actually replaced the thermal paste, and it made no difference. Running FEA won't make it shut down, but USB functions will. My built in keyboard doesn't work correctly, replacement didn't help. So the quality of the whole computer is not up to snuff.

Being retired means I just don't replace stuff, cost be damned. But I can budget and when the time is right, or it croaks altogether, I'll replace it with something, hopefully better. Right now it's functioning as a desktop, using an external keyboard. I can't even login with the internal keyboard, quite a few keys don't work. Would be nice to have a laptop again...
 
WobblyHand said:
It's probably the fact that this computer is a pandemic laptop, ie, not quite made right. Or they used 3/4 of the correct amount of solder paste, or something stupid like that. It's not a CPU thermal thing. Actually replaced the thermal paste, and it made no difference. Running FEA won't make it shut down, but USB functions will. My built in keyboard doesn't work correctly, replacement didn't help. So the quality of the whole computer is not up to snuff.

Being retired means I just don't replace stuff, cost be damned. But I can budget and when the time is right, or it croaks altogether, I'll replace it with something, hopefully better. Right now it's functioning as a desktop, using an external keyboard. I can't even login with the internal keyboard, quite a few keys don't work. Would be nice to have a laptop again...
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Those keyboards are relatively easy to replace and inexpensive +/- 20 bucks.... I am 7 years from my goal of retirement, I am attempting to pick up big items I want for that period, that is why I chose the high end machine, it'll be good for 15 years for what I need it for.
 
verbotenwhisky said:
it'll be good for 15 years for what I need it for.
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Or until the day you get the message that your operating system is no longer supported. Microsoft has turned their back on the past many times, and are doing it more and more since killing Windows 7. They were reluctant to kill XP, and waited a long time, but now they have become decisive and ruthless. Try putting Win 12 on CMOS (non-UEFI) hardware. Oh, wait, you can't.
 
pontiac428 said:
Or until the day you get the message that your operating system is no longer supported. Microsoft has turned their back on the past many times, and are doing it more and more since killing Windows 7. They were reluctant to kill XP, and waited a long time, but now they have become decisive and ruthless. Try putting Win 12 on CMOS (non-UEFI) hardware. Oh, wait, you can't.
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I have a routine which kills their auto version updates, they bit me on Win 10, fool me once.... I was one of the beta testers that got burned in the Windows 95 fiasco, I have no love for Microshaft and I am fairly certain Uncle Bill (the greatest software pirate to ever live) is the Anti-Christ. I once was a super user on Unix so I still view Linux as an option....
 
You can still run anything you want in any year your want, offline. Once you connect to the net, there are some updates you really do want need: the security patches and malware definitions. The world isn't survivable without them, and microsoft is a de facto monopoly. Sorry Apple users, you're a 1% oddity. Linux is the cure if you don't mind working through your OS install and learning open source alternatives.
 
verbotenwhisky said:
Those keyboards are relatively easy to replace and inexpensive +/- 20 bucks.... I am 7 years from my goal of retirement, I am attempting to pick up big items I want for that period, that is why I chose the high end machine, it'll be good for 15 years for what I need it for.
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The replacement keyboard I purchased didn't work either. The problem is on the MB. I actually returned the replacement keyboard, because it too was missing keys.

I had a very nice high end laptop - things were good - until they weren't. The MB failed during the pandemic. I had to transfer all my important stuff to a Raspberry Pi 4 that I had and I used it as my primary computer to hold me over. I wasn't going to service a then 7 year old laptop, so I bought this one. I had to wait over a month for it - because pandemic. As it turns out, it has quality issues. It stinks, but that's the hand I was dealt.

FWIW, I use Linux, now for 20 years, so I am not being held hostage by MicroSoft. Using Linux isn't all peaches and cream, it has it's own issues, but I get by. I learned Linux because one of our customers used it 20 years ago. Kept on using it - mostly because a whole lot of stuff is available open source.
 
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