Anthony.A
Mechanical
- Sep 9, 2024
- 1
Please point me in the right direction if I’m posting on the wrong section.
I’m wrapping my head around the right size (thickness) of the gusset plates on a rubber expansion joint. I’m installing a few rubber exp. joints at the discharge side of pumps/chillers. The conditions are as follows:
Pipe Dia: max. 600mm
Bellow dia: (lets say +20% of pipe dia) 720mm
Operating pressure: 4.6 bar
Testing pressure: 13.7bar
Flow velocity: max. 3m/s
The formula used here is: Thrust = (pi/4)*D^(2)*P
For 4.6 bar case that gives us 187kN, 13.7 bar gives us 557kN. Now if I use 3x M24 grade 8.8 bolts (yield strength 560N/mm2), they could withstand the calculated force. But its so much easier for the gusset plate to bend, and lead to failure that looks like this.(attachment 1) But from most ready-made products/ existing installations, the gusset plate doesn’t exceed 20mm in thickness - so how do they not bend already?
I have also attached the calculation sheet for the M24 bolt and gusset plate as reference. (attachment 2)
Attach. 1: Attach. 2:
I’m wrapping my head around the right size (thickness) of the gusset plates on a rubber expansion joint. I’m installing a few rubber exp. joints at the discharge side of pumps/chillers. The conditions are as follows:
Pipe Dia: max. 600mm
Bellow dia: (lets say +20% of pipe dia) 720mm
Operating pressure: 4.6 bar
Testing pressure: 13.7bar
Flow velocity: max. 3m/s
The formula used here is: Thrust = (pi/4)*D^(2)*P
For 4.6 bar case that gives us 187kN, 13.7 bar gives us 557kN. Now if I use 3x M24 grade 8.8 bolts (yield strength 560N/mm2), they could withstand the calculated force. But its so much easier for the gusset plate to bend, and lead to failure that looks like this.(attachment 1) But from most ready-made products/ existing installations, the gusset plate doesn’t exceed 20mm in thickness - so how do they not bend already?
I have also attached the calculation sheet for the M24 bolt and gusset plate as reference. (attachment 2)
Attach. 1: Attach. 2:
