CosmosWorks Modelling question
CosmosWorks Modelling question
(OP)
Hello,
I'm trying to setup a simple model of a rectangular bolted flange that is under uniform pressure on one side. I wish to examine the resulting displacement of the flange when a bolt is removed under pressure (i.e. will gas escape in this region). The flange is big 10' x 6' x 2" thick with stiffeners, 64 3/4" dia. bolts and 25 psi interior pressure.
My question is what type of restraint do I use for the bolts? I have used radial, axial, and circumferential on cylindrical faces of the bolt holes (all values =0 i.e. fixed) for the bolts and a uniform pressure of 25 psi on the interior face of the flange. When I run the model the von mises stresses are too high at some bolt hole locations. Have I over restrained the bolt holes, if so how do I restrain the model to be more realistic but also stable?
Thanks,
Ed
I'm trying to setup a simple model of a rectangular bolted flange that is under uniform pressure on one side. I wish to examine the resulting displacement of the flange when a bolt is removed under pressure (i.e. will gas escape in this region). The flange is big 10' x 6' x 2" thick with stiffeners, 64 3/4" dia. bolts and 25 psi interior pressure.
My question is what type of restraint do I use for the bolts? I have used radial, axial, and circumferential on cylindrical faces of the bolt holes (all values =0 i.e. fixed) for the bolts and a uniform pressure of 25 psi on the interior face of the flange. When I run the model the von mises stresses are too high at some bolt hole locations. Have I over restrained the bolt holes, if so how do I restrain the model to be more realistic but also stable?
Thanks,
Ed






RE: CosmosWorks Modelling question
Regards
RE: CosmosWorks Modelling question
RE: CosmosWorks Modelling question
Create split lines on you part for the washer faces of your bolts. Do this on the side of the flange that the bolt heads would be. In your FEA, fix these washer faces. Now apply your pressure to the other side. This should show you your deflection between bolts. Now run a second study where you remove one of the bolt restraints. This should show you what happens when a bolt is removed.
RE: CosmosWorks Modelling question
Claudio
RE: CosmosWorks Modelling question
The only accuracy being lost is the axial deflection of the three remaining bolts under the pressure load. That additional deflection is simple to calculate by hand.
deflection = PL/AE