Stochastic analysis of functional failure pressures in glass fiber reinforced polyester pipes

Abstract

• Stochastic analysis of Functional Failure (FF) pressures in GRP pipes is conducted. • Both fiber volume fraction and winding angles are chosen as random parameters. • FF pressures are more significantly affected by fiber volume fraction variations. • Statistical analysis show that most probably FF pressure exceeds its mean value. The main objective of this study is to investigate the functional failure of Glass fiber Reinforced Polyester (GRP) pipes subjected to hydrostatic internal pressure implementing stochastic approach. In this regard, a progressive damage modeling is developed to evaluate the pressure at which weepage takes place throughout the pipe wall thickness. The functional failure implies on a certain pressure that the fluid finds a path through the pipe wall thickness as a consequence of weepage phenomenon. Fiber volume fraction and winding angles in cross plies are considered as the random parameters representing the most important uncertain parameters of filament winding production process. Sufficient numbers of samples are generated using Monte-Carlo technique on the basis of defined convergence criterion. The influence of random behavior of these parameters on the both first-ply-failure and functional failure of GRP pipes are analyzed in an integrated procedure. The results demonstrate that the effect of fiber volume fraction variation on the functional failure pressure is more crucial than that of winding angle variation. Finally, statistical analysis of obtained results is presented on obtained results from stochastic analysis in the form of Weibull probability density function.