Hi all,

I have concern about FRP stress envelope as below:

#1:
What is the purpose of drawing stress envelope in case the CII output report shows all stresses are within allowable? Do we need to draw?

#2:
How to identify which values of Hoop Stress and Axial Stress per each load case SUS, OPE, OCC shall be picked up to indicate on the graph?

There is no "requirement" to draw the stress envelope.
The envelope is useful in illustrating the interaction between hoop stress and the two axial stress components - pressure and bending.

Hi Dave,

FRP vendor report provides envelopes (SUS, OPE, OCC) with indication of maximum calculated stresses in each load case. As you said there is no "requirement". I think these plots is just for reference that the system is safe with max stresses within the envelopes.

However, I'm still be interesting in how to pick up "maximum calculated stresses in each load case" to draw them in the envelope. Since Max Axial stress and Max Hoop stress may not from the same node.

Any advice will be very appreciate!