Experimental and theoretical investigations on the failure of filament wound GRP pipes

Usually, Glass Reinforced Polyester (GRP) pipe industry uses simple netting analysis to predict longitudinal and apparent hoop tensile strengths during structural design procedure. Along the simplicity of this method, it underestimates/overestimates the strengths resulting in over designed and expensive pipes or unqualified pipes. A sequential failure modeling which is suitable for laminated composites with quartz sand core is developed to overcome this difficulty. A computer code is written to calculate mentioned strengths using winding angles, number of layers and sand ratio as the main input parameters. A comparative study is performed between results obtained by netting analysis and developed sequential failure modeling. A complete set of experiments have been carried out on different ranges of diameters and pressure classes of GRP pipes to determine the suitability of developed method. It is observed that developed modeling for GRP pipes with sand filler predict strengths of pipes with high level of accuracy.