Modeling and experimental evaluation of functional failure pressures in glass fiber reinforced polyester pipes

The main objective of this paper is to predict the functional failure pressure of Glass fiber Reinforced Polyester (GRP) pipes subjected to hydrostatic internal pressure. A progressive modeling procedure is developed to predict the internal pressure associated with weepage. The developed modeling consists of stress analysis, failure evaluation and material degradation. The influence of micromechanics rules for estimating mechanical properties of constructing layers and failure criteria for predicting failure occurrence are examined in comparison with experimental observations and the best combinations of them are identified. First-ply failure and functional failure pressures are determined and compared. A parametric study is conducted investigating the effect of fiber volume fractions and winding angles on the failure pressures. The study is performed on five different volume fractions of 52.5%, 55%, 57.5% and 60% and three different winding angles of 52.5 degrees, 57.5 degrees and 60.19 degrees. The results show that the functional and first-ply failure pressures decrease by increasing fiber volume fractions; while the higher winding angles (measured from the axial axis of pipe) enhance functional failure pressures. (C) 2014 Elsevier B. V. All rights reserved.