Calculating Burst Pressures

[BrettARichard]

I'm working on a tight tolerance design, and i need to calculate a burst pressure for the main body of the part and also the oring groove. Could someone send me in the right direction? What equations should be used? I'm assuming this would be considered and treated as a thin-walled pressure vessel...

OD of Body=1.738"
ID=1.5"
OD of o ring groove=1.582"
Oring groove is .27" wide
Material is 4140 Q&T, MYS=110ksi

 

[metengr]

As a first approximation for burst pressure, you could use the standard hoop stress formula for a thin-walled cylinder;

hoop stress = (pressure * outer radius)/wall thickness

Set the hoop stress = ultimate tensile strength, and solve for pressure

The o-ring groove will be the source of stress concentration, and most likely will be the location of failure.

You could use this same equation and substitute the ligament thickness for wall thickness (wall thickness - o-ring groove depth) and solve for burst pressure.

 

[carthago]

I believe Harvey in his "Presure Vessel Design" has a chapter abothis.