Is this correct: center of buoyancy = center of mass when submerged for an object of uniform density?
You could do a Save-as --> Part in a way to save only outside surfaces, then fill in the interior. This would give you the center of displaced volume.
SolidWork does not posses this capability.
Roland, thanks but I don't think that works.
Eddie, I am afraid that this is the correct answer. As much as i don't want to hear it.
Charles, I've already read that thread and it's not what I'm after.
Thanks for the quick replys guys!!!
Dug up one of my old naval science textbooks...
Center of buoyancy IS center of mass of displaced water.
turn assembly into part (Save as --> Part)
fill all voids until everything is solid
set density to same as water (1g/cc for fresh water)
get CG of filled part, this will be center of buoyancy when submerged
It really is that simple
actually, location of CG will be same regardless of density, but with density set to same as water you can get mass of displaced water, which you will need to calculate total buoyant force
You may continue to think it doesn't work. You can even say I am wrong. You can't say Dutton's is wrong.
More about buoyant force...
As was stated before, buoyant force is equal to the weight of the displaced water, centered at the CG of the displaced volume of water. There is no need to add all the vectors of the individual components.
Keep in mind that the center of buoyancy is usually not the same as the center of mass, especially if there are hollow components. Thus, an untethered submerged object at rest will be stable when the center of mass "hangs" below the center of buoyancy.
When the center of mass is not in vertical alignment with the center of buoyancy, the object will experience a righting moment proportional to the cross-product of the difference between buoyant force and weight and the distance between the two centers.
Take a submerged object held in a random orientation. If the center of mass is not aligned with the center of buoyancy, the object will experience a righting moment. An equal and opposite counter-moment will be required to hold the object in that orientation.
The stability of a floating object also depends greatly on this righting moment. A boat will not capsize as long as the center of mass stays below a point where the righting moment does not get reversed, which would result in the boad being flipped in the opposite direction.
Plenty of additional info available on Wikipedia. Most of it looks kosher.
Old thread I know, but I wrote a macro recently that does just this. It will create a 3D sketch point at the Center of Gravity and the calculated Center of Buoyancy. I will upload here in the hopes it will help someone as I've seen this question asked a few times.
Macro1.dll.zip 6.1 KB
I look forward to trying your macro. I have done bouyancy and righting moment calculations manually by slicing at the water plane.