Determining support body

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Determining support body

Postby Cannos » Tue Oct 09, 2018 12:14 pm

I have an object (A) at rest on top of 2 other objects (B and C) (see picture). Is it possible to determine if the object is stable on 1 object more than the other? More specifically, I'm trying to find out if A will remain at rest on top of B if I were to remove C. Or will it tumble off.

I was doing a simple check to see if the center of mass of A was above B or C, but that doesn't seem to be enough in some cases close to the edge.

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Re: Determining support body

Postby JernejL » Tue Oct 09, 2018 12:27 pm

I think you could check rotational omega, and see if it's enough to sufficiently move the body, i'm not sure about the math, because you might need to take friction and orientation into account.

Or just simulate a few moves in a parallel newton world and see if it falls off :) Newton is fast.
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Re: Determining support body

Postby Julio Jerez » Tue Oct 09, 2018 3:25 pm

that's actually quite hard problem to do reliably.

for a simply cases like you describe you can get the contact joint between the two bodies, and get the reaction forces.
the body will stable if the forces are small compared to the body weight, however this is just a necessary condition but not a sufficient.

it will work must the time for object on the border of a pile. for bodies on a stack the joint force most the time will be huge, so it will say not that object can't be lifted, however is posible that the body still can be lifted.

basically it will always give you a conservative answer, that can be false.
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Re: Determining support body

Postby Cannos » Tue Oct 09, 2018 4:13 pm

Thanks, I'll check that out.
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