Simulation of functional failure in GRP mortar pipes

The main objective of this article is to simulate and analyze the functional failure in composite pipes subjected to internal hydrostatic pressure. A progressive damage modeling is developed taking into account the influence of core layer incorporated in order to increase the pipe stiffness. The modeling procedure consists of four parts as model preparation, stress analysis, failure evaluation and degradation rules. The developed modeling is validated using experimental results of a composite pipes consisting of FRP and sand layers. The influence of two main parameters as core thickness and the winding angles of cross plies are investigated. It is observed that First-Ply-Failure (FPF) and Functional Failure (FF) pressures increase linearly with increasing the core thickness; however the relative difference between FPF and FF pressures decreases. Three types of boundary conditions imposed from most common experimental setups are also simulated and analyzed. The variations of FF versus winding angles are investigated for all three sets of boundary conditions.