How to calculte centre of gravity using theoretical way

SYED BASEERULLAH
Member • Jun 17, 2013

How to calculte centre of gravity using theoretical way

This is the problem i am facing, i would like to design a car and for that centre of gravity is an important factor which rules traction and steering effectiveness. My problem is about calculating C.O.G. i know the weight of car,trackwidth and wheel base . but i don't know the weight distribution on front and rear tyres, as it depends on gravity point to calculate.can anyone help me with formula and concept to calculate it.

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Gurkirat Singh

Member • Jun 18, 2013

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zaveri

Member • Jun 18, 2013

Gurkirat Singh
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Gurkirat Singh

Member • Jun 18, 2013

I was talking about International Gokart championship...to be organised by LPU SAE india collegiate club
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SYED BASEERULLAH

Member • Jun 18, 2013

CEan's plz help me out directly rather than refering me for some online calculators and all sort of things.
let me know the factors i have to assume to start working on it

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white_hat

Member • Jul 1, 2013

#-Link-Snipped-# , is it about your buggy build?? Well I do not know any theoretical method.But in the whole setup the driver and the engine+gearbox are having maximum weight.So I would try and bring them closer to each other and as lower as possible.

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Sanoj Rajan

Member • Jul 1, 2013

To Calculate CG, is no tough job. Though, what i am going to suggest may not be the right way.

Start with single dimensional approach. Pin point the weights of the major components of you car.

Now, lets get to 2D. Assign these pin pointed weights some Cartesian coordinates according to their position, using some software, or on a graph paper (if you want to go with "more with less" concept ).

If you are going to do it on a paper, take 3 papers, for:
1) Front View
2) Top View
3) Side View

For each view, find the CG. (Assuming you know the formula for that 😉 )

If you have did it correctly, the CG in each view will coincide, and voila, you got your answer. 👍 Thank me later. 😛

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white_hat

Member • Jul 1, 2013

Sanoj Rajan
To Calculate CG, is no tough job. Though, what i am going to suggest may not be the right way.

Start with single dimensional approach. Pin point the weights of the major components of you car.

Now, lets get to 2D. Assign these pin pointed weights some Cartesian coordinates according to their position, using some software, or on a graph paper (if you want to go with "more with less" concept ).

If you are going to do it on a paper, take 3 papers, for:
1) Front View
2) Top View
3) Side View

For each view, find the CG. (Assuming you know the formula for that 😉 )

If you have did it correctly, the CG in each view will coincide, and voila, you got your answer. 👍Thank me later. 😛
Even if you do this maybe we can get approximate line in which CG is acting.CG can be anywhere on that line , it can be below ground level also.
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You know what , find someone who knows CATIA ,make a 3D model and input all the weights and the software will find out the CG for you , I think thats what you should do #-Link-Snipped-#.

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zaveri

Member • Jul 2, 2013

From what i have known, the C.G lies mostly below the chassis frame, and above the ground and does not fall on some physical object.

in such cases, the calculation is quite complex i believe. so better refer some SAE guide books.

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Sanoj Rajan

Member • Jul 2, 2013

white_hat
Even if you do this maybe we can get approximate line in which CG is acting.CG can be anywhere on that line , it can be below ground level also.
.
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You know what , find someone who knows CATIA ,make a 3D model and input all the weights and the software will find out the CG for you , I think thats what you should do #-Link-Snipped-#.

Buddy, if the 3 graphs i told about, is done correctly, all these points will coincide, n won't make a line.

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Sanoj Rajan

Member • Jul 3, 2013

zaveri
From what i have known, the C.G lies mostly below the chassis frame, and above the ground and does not fall on some physical object.

in such cases, the calculation is quite complex i believe. so better refer some SAE guide books.

lower the CG, better the handling. But as per my knowledge, the CG won't be below the chassis. And its not true that if CG doesn't lie on the object, the calculation becomes complex.

Take this example: the ring we wear on our finger, is circular in shape. Assuming equal density distribution, and flawless finishing, the CG will be exactly in the centre of the ring, which by the way is the hollow space, rather than being on the ring itself. And according to me, this was damn easy calculation.

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Sindhu Chowdary

Member • Jul 3, 2013

Center of Gravity is the center of object's weight distribution , where the force of gravity is considered to act.
<a href="https://www.wikihow.com/Calculate-Center-of-Gravity" target="_blank" rel="nofollow noopener noreferrer">5 Ways to Calculate Center of Gravity - wikiHow</a>

May be this will come to your help.

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white_hat

Member • Jul 4, 2013

Sanoj Rajan
Buddy, if the 3 graphs i told about, is done correctly, all these points will coincide, n won't make a line.
In Strength of materials and structural engineering i learned how to find out the resultant force and line of action of resultant force, so from what i have learned i do not think i could solve that, my bad, sorry.

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Sarathkumar Chandrasekaran

Member • Jul 8, 2013

Please refer automobile mechanics by N.K.Giri.
I haved read the same in last semester on weight distribution and there is a simple formula for it in book using wheel base , height,etc

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Ramani Aswath

Member • Jul 8, 2013

One way could be to find the CG of each sub assembly, which is simpler. Assign each of these to the weight of that assembly and locate these points in the 3D space. Take these points in pairs and find the CG of the pair. Continue iterating till you get the CG for the whole assembly.

It is painstaking but a no brainer.

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SYED BASEERULLAH

Member • Jul 9, 2013

white_hat
#-Link-Snipped-# , is it about your buggy build?? Well I do not know any theoretical method.But in the whole setup the driver and the engine+gearbox are having maximum weight.So I would try and bring them closer to each other and as lower as possible.
yeah it's about buggy build

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The Observer

Member • Jul 28, 2013

Theoretically.. it is done using front and rear axles loads. Am not much sure. Did that long back.

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SYED BASEERULLAH

Member • Aug 4, 2013

Thanks to all,i have successfully calculated cog of my buggy

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