Member
Posts: 3
Registered: ‎12-22-2012
Message 1 of 7 (1,310 Views)

# Center of Gravity

1310 Views, 6 Replies
12-22-2012 07:39 AM

Hello, is it possible in AUTOCAD to know the CENTER OF GRAVITY OF A VEHICLE?

I am a physicist and I need to verify my result in getting the COG of a vehicle design. I knew nothing from AUTOCAD so I am asking for your help guys! Thanks a lot!

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Registered: ‎08-16-2007
Message 2 of 7 (1,304 Views)

# Re: Center of Gravity

12-22-2012 10:42 AM in reply to: roeljohn

It'd probably be easier to build the car and then put it on a set of scales than to model an entire automobile in AutoCAD just to find that coordinate.  AutoCAD can easily determine the center of mass of a solid with a unit weight of 1.  You would need to separately calculate the solids of each specific gravity and then do a weighted average on your own.

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Registered: ‎12-22-2012
Message 3 of 7 (1,300 Views)

# Re: Center of Gravity

12-22-2012 11:47 AM in reply to: roeljohn

Okay buddy thanks! So your are saying that it is easier and reliable to solve it on pen and paper?

Model each part then solve for the specific gravity of each then do a weighted average? <- is this one possible in CAD?

But do you know other methods on how can I verify the calculated COG?

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Registered: ‎08-16-2007
Message 4 of 7 (1,278 Views)

# Re: Center of Gravity

12-23-2012 11:40 AM in reply to: roeljohn

If you just modelled the primary steel parts with solids and ignored the foam, plastic, skin, and wiring, you should be able to get pretty close.  Sticking with a single material could give you a pretty good idea.  Once you've done the solid modelling, use the massprop command.

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Registered: ‎04-20-2006
Message 5 of 7 (1,265 Views)

# Re: Center of Gravity

12-24-2012 05:35 AM in reply to: roeljohn

roeljohn wrote:

<- is this one possible in CAD?

Autodesk Inventor.

Getting the COG is trivial (Inventor iProperties will calculate that for you), the work is in modeling the vehicle.

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Posts: 3
Registered: ‎12-22-2012
Message 6 of 7 (1,258 Views)

# Re: Center of Gravity

12-24-2012 05:47 AM in reply to: roeljohn

Right now, I am still looking for CAD expert to make a model of my own vehicle, I am a physicst and very much new to CAD softwares (except Google Sketch Up), then I will ask him to do your suggestions by the way, can somebody do a modelling for me? I am willing to pay

Active Member
Posts: 6
Registered: ‎12-05-2012
Message 7 of 7 (1,236 Views)

# Re: Center of Gravity

12-25-2012 10:34 PM in reply to: roeljohn

How mathematically oriented are you going with this?

I would say to start at the dead center of the car, and calculate the moments about the center of gravity at either the front and rear axles or the very front and back of the car (this is probably better). When they are equal to each other, you've found the center of gravity.

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