FRP Pipes being Orthotropic requires 9 Independent Material constants. We give input only for 4 in CAESAR II. Why?

Barurao:

As far as the 9 material constants are concerned, I assume that you are referring to Ea, Eh, Er, Ga, Gh, Gr, phiah, phihr, and phira.

From a pipe stress point of view, all piping codes (at least those that CAESAR II supports) ignore the radial stress, so that leaves us with Ea, Eh, Ga, Gh, and phiah.

Likewise, from a pressure piping point of view, hoop shear is just about non-existent (and therefore also ignored), so that leaves us with Ea, Eh, Ga, and phiah, the four properties that CAESAR II really needs to do its analyses.