I am running a Caesar 2 analysis for an operational case.

I am running into an issue where there are no stress values shown in the stress report for the flanges, has anyone seen this before?

There are local element forces on the flanges so I would expect there to be stresses. has anyone seen this before?

Your phrasing leads me to believe you're new to pipe stress analysis.

If so, welcome.

But you should be very cautious in how you proceed if you've been thrusted into CAESAR without proper training.

"Rigid elements" don't have stresses calculated for them. It's not typical for stresses in flanges to be calculated. There are flange checks, however, that check for leakage, but not stresses in the actual flange.

Hello, I am indeed new to pipe stress analysis.

Please could you let me know why it is that stress in the flanges is not calculated?

As Michael mentioned, there are flange checks and other things you can use to see if the flange is overloaded.

In general, the piping specification you're designing to should be adequate for the flanges allowed in that spec (meaning piping flange pairs). Other flanged connections, such as tank/equipment nozzles, should be evaluated and ensure they don't exceed their allowable loads.

But rigid elements in Caesar do not have allowable stresses. They still experience thermal growth/contraction, which makes them ideal for representing valves or centerlines of equipment connected to your piping.

By and large, the flange seal will fail before the pipe metal will fail, which will fail before the metal flange will, assuming you're using standard flanges.

Thus, a flange stress check is largely academic, unless you have non-standard connectors, in which case, you're better off getting allowable loads from the manufacturer (except they rarely will offer such a thing).