Hello all,

First of all, I want to salute all this piping community, as I am new at it.

My question is about properly imput of FRP properties in Caesar.

The vendor gave me these values:

Young's modulus - axial : 13000 MPa

Young's modulus - radial : 13000 MPa

Poisson's ratio (principal): 0.4

Poisson's ratio (secondary): 0.58

The only value I am sure is the first one, but I am a bit loose with the other three values, how can I imput them?

Thank you very mucha in advance.

May I ask which piping manufacturer gave you this info? It is very rare to have an FRP pipe with Young's modulus axial = Young's modulus radial.
the "poissons ratio" can be entered in the Vh/a * Eh/Ea field underneath the Young's modulus input field.
Be careful here. Some manufacturers give the real Poisson's ratio, some give the recalculated one with Eh/Ea already in it. The documentation mostly says poissons ratio in both cases though.

Are the allowable stress values also the same in both directions?

Thank you very much corne, I have mistaken, the right values are:

Young's modulus - axial : 13000 MPa

Young's modulus - radial : 20000 MPa

Also, the allowable stress values are NOT the same in eacha direction.

Thanks again-

That seems more likely indeed.
In CII you only have to enter the axial Young's modulus. A factor hoop/axial or axial/hoop must be entered depending on the code you're using. Check all the input boxes (using help function) in the allowable stress input sheet.
The way you can check the maximum occuring stress also depends on the way the manufacturer has determined the maximum allowable stress by the way.

Hi corne,

Really would appreciate a follow up on your comment regarding poisson ratio. Under the classic piping input, the poisson ratio is shown as Ea/Eh*Vh/a whereas you say it is entered under Vh/a*Eh/Ea. I was given a value by the manufacturer for Poisson ratio Va/h = 0.4. Is this the correct value to input in CII? Should they also give me a value for Vh/a? If so then I can give the full answer since they have given me Ea and Eh value.

On another matter can't seem to find the relevant post but you did say that there was an Ameron technical bulletin regarding developinga failure envelope. Would you have a copy of this as it was not available from their website. Thanks.

That was my mistake I guess. I was typing my comment at home so no way to double-check if I had the formula correct.
If you change the design code in CII from for example B31.3 to a FRP code, the poisson ratio input box becomes the Ea/Eh*Vh/a input box. The value of 0.4 is the value you want to enter there.
A lot of manufacturers call what they adress in their technical specs the poisson ratio, but it actually is the poisson ratio * Ea/Eh and is most likely to be around 0.4.

I don't have the Ameron document here at home, but it has more or less the same info as the Coade document about ISO 14692 calculations as that calculation method works with the envelopes too.