Calculating Bursting Pressure of a Pipe Cap

[darkelf]

Hello,

I'm trying to calculate the bursting pressure of a pipe cap or the end capped pipe. I need to know how much pressure will cause the cap of the pipe to burst or deform.

I have the bursting pressure of the pipe, so its the cap bursting pressure I need to calculate

Here is a crude schematic of what I am referring to, where '=' is the pipe and 'D' is the cap =D

I need to compare if it is better to have a curved cap of if a flat plate would better hold the bursting pressure i.e. =l

Thanks guys

 

[Unrest]

A flat plate holding pressure is also called a diaphram. All the load is carried by bending stiffness so it has to be quite thick.

A dished end cap may have a combination of bending and tension (membrane) stress.

A hemispherical end cap has only membrane stress, so it could be made with a very thin, flexible material. It's relatively easy to find the stress here. It's the same all over it, so just calculate the stress around the connection to the pipe by using stress = F / A where A is the cross-section of the material and F is found from the pressure and area of the circular pipe.

In either case, you'd need to find the 'worst' stress state and compare to the yield stress of the material. Because it's not uni-axial stress, you may need to use a von Mises equivalent stress or something.

http://www.webcivil.com/circslab.aspx

 

[edgepflow]

There are also formulas in the ASME Boiler & Pressure Vessel code for caps. Machinerys Handbook has formulas for loaded plates. Like the last post said, the material will start to yield (deform) at the yield stress and likely fail at the tensile strength.