Hi All ,

I have some doubt on UKOOA stress envelope calculation, by refer to the standard i cant really understand . It quite hard for a beginer like me to learn directly from the UKOOA standard ,do anyone in the forum know the simplified method to learn UKOOA stress envelope calculation ?

Regard Glenn

The envelope is specific for each FRP pipe type of material. Ask your vendor if they provide it. I think we don't calculate it. I think it's like having the Yield strength of such material from testing. FRP pipe is unique and we consider the combination of hoop and axial stresses if they are still falling inside the envelope. You may observe *.frp file (notepad file) in Caesar directory and search using keyword FRP in c2TR.pdf file.

There is a good document from Ameron called "Failure characteristics of Baondstrand Glassfiber reinforced epoxy pipe" about determining the GRP material data and the development of the envelope.
That in combination with a document coade uses to explain GRP modelling in their classes can help you greatly to learn the basics of this.
I recently had to make a summary for a client explaining the differences between UKOOA and BS7159 and used both documents as a source.

Glenn,

I think it would be better for you to consult your senior engineer, and read the UKOOA code specifically chapter 3 of part3.

UKOOA's code:

PDm/4t < f1f2f3*LTHP

for anisotropic material: f3=1-(2Sab/r*f1*LTHS), this factor involves the relation between pressure induced axial stress and pressure induced hoop stres, which means 50% of avaliable axial strength is available for additional loadings.

Thus, CAESAR uses:

Sab(f2/r) + PDm/4t < f1f2LTHS/2.0 (you can derive this by using simple equations from the code)

For the rest, you have to read the text.

Goodluck!

Ok . Thanks for all bro guidance , i will find out based on the recommendation . highly appreciate

Glenn koh