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# Trailer roll over

## Trailer roll over

(OP)
Hi,

On a trailer a product with a high C of G is being tranported. The product still getting larger and the C of G is also getting higher. Is there an easy way of calculating the stability against rolling over.
Driving at low speed (walking speed) Turning corner radius is small and heigh weights about 50.000 kg. There are some small slopes in the corners. Transports are looking scary when we are increasing the product dimensnions again.

I have searched the internet, and found a lot of documents. I cannot get a start on an equation which could help to solve our worries and keep a safe transport.

All help is appreciated.

Johg

### RE: Trailer roll over

Find center of mass, then draw triangle. CoM to tipping edge (wheel), CoM horizontally towards acceleration of curve.

Really, a practicing mechE that can't do what amounts to a static diagram?

Dan - Owner
http://www.Hi-TecDesigns.com

### RE: Trailer roll over

Well, ignoring that subject for the nonce, it's what, a 30-second websearch?
https://www.accidentreconstruction.com/research/su...[1].pdf

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### RE: Trailer roll over

Johg:
This problem is addressed all the time when dealing with High, Wide & Heavy Load (HWHL) transportation. MacGyverS2000 is right, draw and end view of the trailer and load, and keep the resultant force vector inside the lower wheel line and you should not tip over on a slope. But, don’t forget that that lower tire will be over loaded and deflected more than the high side tire, for some added tipping effect. You pick the/your factor of safety against overturning. Regarding speed, centrifugal force can hurt you, and don’t count on it ever helping you. You could counter-weight the trailer down at the trailer deck or lower to help lower the total C.G.

### RE: Trailer roll over

"don’t forget that that lower tire will be over loaded and deflected more than the high side tire, for some added tipping effect." True, also more deflection here if the trailer has springs on the axles.

Centrifugal force can (and should) be also accounted, Fc = M V^2/R, where Fc is the centrifugal force (acting nearly horizontal at the center of mass, M), V is the trailer horizontal velocity, and R is the radius of the path followed by the high/heavy mass. This formula is dimensionally consistent in any system of units, conforming to the fundamental F = MA. The free body diagram will have the gravity vector acting downward, plus the centrifugal force vector horizontal, or sloped as the radius vector if the radius vector is not horizontal.

As stated previously, be sure to add a safety factor to account for vibrations in suspension system, bumps in the road, possible other factors such as wind (yes, wind has helped to turn over many trucks and trailers, even without your specifics), etc.

Also, as posted previously: "Really, a practicing mechE that can't do what amounts to a static diagram?" (What I call a "free Body Diagram" above). If you do not clearly understand how the "static diagram", or "free body diagram" applies here, then do not risk failure here, fully understand, or find someone who does understand to solve the problem.

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