ISO-14692 addresses the analysis of Fiber Reinforced Plastic (FRP) pipe. Qualification is based on the comparison of actual stresses, hoop and axial, to a failure envelope. See BS 7159 for the CAESAR II approach for FRP pipe analysis.
ISO-14692 2017
ISO-14692 2017 distinguishes between the reinforced wall thickness and the total wall thickness. The reinforced wall thickness does not include the liner (inside) and sheath (outside) the reinforced wall. In CAESAR II, define the reinforced dimension (not including the liner and sheath) for Diameter and Wt/Sch, and separately define Refract Thk, Refract Density, Liner Thk, and Liner Density.
ISO 14692 2017 defines four axial code stresses and a single hoop code stress, and has a single allowable failure envelope. The vertical axis defines the axial stress and the horizontal axis defines the hoop stress.
Stresses (Multiple Code/Allow) Report for ISO-14692 2017
CAESAR II picks a single "worst" axial stress from the four code stresses and displays this value in the Stresses (Multiple Code/Allow) Report.
If all four axial stresses are inside the failure envelope, then the software subtracts the axial stresses from their respective envelope allowable. The smallest difference determines the worst axial stress and allowable. The software compares each axial stress to both the tensile and compressive boundaries of the failure envelope.
If one or more axial stresses are outside the envelope, then the software subtracts the axial stresses from their respective envelope allowable. The largest difference determines the worst axial stress and allowable. If only one axial stress is outside the envelope, then this is the worst axial stress.
The hoop stress and the allowable hl(2:1) also display in the report.
Stresses Report for ISO-14692 2017
The governing code stress displays in the Stresses Report.
If the worst axial stress and hoop stress are both inside the failure envelope, then the software determines the ratio between each stress and its allowable. The software uses the stress with the highest absolute value ratio as the code stress.
If the axial stress is outside the envelope and the hoop stress is inside, then the software uses the axial stress as the code stress.
If the hoop stress is outside the envelope, then the software uses the hoop stress as the code stress.