3d Center of mass

[ercegs]

Hi,
Can someone recommend me a good website on how to calculate Center of Gravity in 3D, or some literature?

I have to calculate the COG of complete vessel with skid which is beside vessel.

Thanks in advance

 

[jmiles]

Hi,

There are many CAD software packages that will give you a precise and accurate answer, however if you only need a ballpark answer you can make some assumptions and get close to the real answer.
For example if you have a horizontal vessel on a rectangular skid you can assume the vessel to be a cylinder and the skid to be a flat plate, take the center of gravity for both as being the direct centers, and then calculate the total center of gravity from that. this oc course ignores non symetries in both the vessel and the skid, as well it will ignore piping and such,you have to use your own judgment to determine if you can ignore these.

basically to get the final COG you want to sketch out the location of both COG's with respect to any datum point, then take the weighted average of their positions, (mass1 x X1 + mass2 x X2)/(mass1 + mass2) repeat in the Y and Z coordinates and you have a rough center of gravity.

If you want to work out the precise COG, you need to frind the COG for each shape on the skid, and located it and its mass, then use this above procedure for every item, personally id build a spread sheet, but in reality its pointless to do unless you have to. Use a CAD package to get the answer if at all possible.

 

[Ganfoss2]

Hi,

Confirmed! Use USER MADE EXCEL WORKSHEETS or any 2D/3D CAD!

Very difficult to get FULL DETAILED SUMMARY WEIGHT LIST and COG evaluation (empty, operating, testing) of a whole vessel with a classical Pressure Vessel Rating Software (i.e.: FINGLOW, APV, COMPRESS, SANT'AMBROGIO NEXT GENRATION, ... others).


It would be very helpfull!

ANN