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willc2  
#1 Posted : Thursday, March 3, 2011 6:34:13 AM(UTC)
willc2

Rank: Junior Member

Joined: 9/28/2008(UTC)
Posts: 19

I was setting up my new dual monitor stand the other day and nearly lost both monitors when it started to tip over. I lowered the mount arms and all was well. But that got me to wondering if ViaCAD could have predicted the tipping over.

My math wasn't up to the challenge of calculating the forces involved but I see that ViaCAD can calculate the mass and center of gravity of any solid. Can one of the big brains on the forum tell if there's a quick and dirty way to tell if a shape would fall over, just using what ViaCAD knows?

For simplicity let's assume the shape is all one rigid part made out of wood, sitting on a wooden table. Also assume all the shapes are simple blocks, cylinders and planks.

Bonus points if forces can be shown just with geometry.

Is anybody up to the challenge?
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zumer  
#2 Posted : Thursday, March 3, 2011 7:44:23 AM(UTC)
zumer

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You can tell if the model you've described is going to fall over, and you don't need any more geometry than knowing that if the CoG is outside the perimeter of the foot - whoopsie. But it's more involved for the real-world instance, because the assembly isn't a single solid part of homogeneous material, so you'd have to represent each member of the assembly with mass and CoG relative to each other before adding them. If you did that, VC would give you the right indication.
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willc2  
#3 Posted : Thursday, March 3, 2011 8:19:17 AM(UTC)
willc2

Rank: Junior Member

Joined: 9/28/2008(UTC)
Posts: 19

So I lightened the monitor slab and extended the foot and sure enough, c.o.g is now within the perimeter of the foot. For more accurate results I guess I could resize the component parts until they have the right relative volumes/masses.

UserPostedImage

Awesome! ViaCAD is to mechanics what notepad.exe is to programming. :)

Thanks zumer
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Jean-Francois Jacques  
#4 Posted : Friday, March 4, 2011 11:03:07 AM(UTC)
Jean-Francois Jacques

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Your foot print is still small. In theory your stand is "stable". But if you touch the front, your model will move down easily.
METEORE DESIGN / KEKO Stand
Jean-Francois Jacques, Industrial Designer
SharkCad Pro V14 B1653
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jol  
#5 Posted : Friday, March 4, 2011 11:07:40 AM(UTC)
jol

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>>Your foot print is still small

.. or more weight at the back of the foot !?
NickB  
#6 Posted : Friday, March 4, 2011 11:36:14 AM(UTC)
NickB

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You can also assign different material properties and weights to each part to get a better idea of where the CG might be.

Verify > Properties
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