Failure Analyses of Propagation of Cracks in Repaired Pipe Under Internal Pressure

In this study, the analysis of the behavior of circumferential through-wall cracks in repaired elbow with bonded composite patch subjected to internal pressure is performed using three-dimensional finite element analyses. The effect of length cracks, the wall thickness (Rm/t), angle of the elbow (ψ) and properties of the patch is presented for calculating the stress intensity factors. The obtained results show that the bonded composite repair significantly reduces the stress intensity factors at the tip of repaired cracks. The Monte Carlo method is used to predict the distribution function of the mechanical response. According to the obtained results, we note that the crack length variations are important factors influencing the distribution function of KI. The uncertainty in this parameter has a significant effect on increasing the probability of failure of pipe and reducing the durability of structure.