tripod stability calculation?

[jscotty29]

can anyone help me calculate the force required to tip over a tripod. i have a pole that is supported by a tripod and i need to determine how much wind force is required to tip the tripod over. thanks ahead of time.

 

[TomBarsh]

I remember getting flummoxed by this sort of problem in freshman "statics" class; then it was a table on four legs. The key is to consider the discontinuity in the equations of equilibrium.

"By inspection" it's apparent that the tripod will pivot in a vertical plane about the base of two of the legs. In a real Nor'easter I suppose the tripod might pivot about the base of only one leg. But such a condition is not especially stable, it is mathematically "chaotic".

Anyway, consider the bending moment (wind) needed to hold the tripod in equilibrium when the force at the third leg is "0". 0 force on the third leg equates to the tripod losing contact with the ground; any additional bending moment will cause the tripod to fall over.




Tom Barsh
Codeware Technical Support