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View Full Version : Rigging Restraints & Force Required to Restrain an object


glocki35
Oct15-09, 12:29 PM
Hi All,

If I have an object (see drawing in attachment), of 6.09 m in height and a distance to C of G = 0.79 m, how can I work out what restraint would be required to stop this object from toppling over if enough force was placed on the structure to make it topple? (assuming a flat surface)

The weight of this object is 496 Kgs and is supported by x 4 ‘outriggers’ to support the structure, I have worked out the potential energy (or work required to tip the object on a flat surface)of this to be 3843.95 Joules or n/m.

Distance between outriggers is 1.58 m across ‘wheelbase’, it is 1.35 m across the width of the structure

My aim is to make a recommendation on a suitable figure for a restraint method, best case scenario would be to secure this object at all 4 corners or ‘outriggers’, with something like a ratchet strap…

This is part of a larger problem I have been working on (THANKS NVN), this is the last part to solve of this problem, I am a little stuck!

Thanks kindly for your assistance.

Glocki 35

mgb_phys
Oct15-09, 12:54 PM
You also have to consider why it would topple over.
Simply working out the minimum force needed to over the minimum distance to provide the energy to topple it doesn't really apply if you put this on a truck and do 2g worth of braking - or go round a bend at 55mph.

If it's going to be moving think of the maximum acceleration - then use F=ma to get the force, then double that, then apply that to each strap, then double the number of straps!

glocki35
Oct19-09, 09:36 AM
Thanks mg_phys, i will do that, much appreciated :)