Probabilistic fracture assessment of piping systems based on FITNET FFS procedure

A probabilistic method based on the fracture module of the FITNET FFS procedure is developed to perform the structural integrity analysis for piping systems. Monte Carlo simulation is used to calculate the failure probability of the whole piping system, as well as that of separate defects by considering the random variables in the method. Both the sensitivity of uncertainties of variables and the model sensitivity are analyzed to identify the most important parameters that affect the failure probability of piping systems, thereby providing an insight into the countermeasures against the failure risk. The results show that the outer diameter of the pipe has the strongest influence on the failure probability of a piping system having a circumferential crack of 0.757 rad, followed by the bending moment, the piping wall thickness, the fracture toughness, the crack angle, the axial force, the ultimate tensile strength and the yield stress.