Two Piece Pipe Clamp Connection

[shockey25]

Hello All

I have a two fold question/challenge regarding a split clamp. What I mean by a split clamp is two piece clamp per attached image.

The initial question I have is regarding correct calculation of the inward force exerted on the pipe, how is the inward force correlated to the tension in the bolts?
I can provide the bolt material - B7, yield strength ~724MPa, assumed Cof ~0.2 and aiming to use no more that 80% of yield. M20s /3/4UNCs provisionally but could increase

The second part of the challenge is connecting a lever arm into this clamp and rotating it, aiming to put a twist into the pipe, assuming it is clamped at the other end. In this scenario.I wish to ensure that my clamping force is sufficient to prevent the pipe slipping. I would intend to place a rubber pad between the pipe and the clamp wall to increase and normalise the COF. In this case I'm looking to find the relationship between the torque applied to induce a 2 degree twist in the pipe (8,126Nm) and whether the clamping force with the benefit of the high COF rubber will prevent it moving under this applied torque

Thanks

 

[1503-44]

Generally tension force in one bolt is roughly considered to be Pressure(your little red arrows) x Clamp length x Pipe diameter / 2

Applying a torque through the clamp may change the above assumption, as the torque applied will tend to increase both and may reverse one of the clamp's bolt loads to counter the torque. If the torque is high, you might have to increase the bolt tension to ensure that both bolts remain in tension as the torque is applied, otherwise you might decrase friction over half the clamp.

The torque applied to the pipe from the clamp (through friction) is T in the following formula

Torsional Angular Deflection of the pipe is,
θ = 32 L T / (G π (D4- d4))
Where:
θ = angular shaft deflection (radians)
T = torque (N-mm, in-lb)
L = length of shaft (mm, in)
G = modulus of rigidity (Mpa, psi)
J = Polar moment of inertia (mm4, in4)
D = outside diameter (mm, in.)
d = inside diameter (mm, in.)



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