Experimental investigation of the effect of winding angle and hybridisation on mechanical properties of polymer matrix composite pipes

In this thesis, it is aimed to produce composite pipe materials with different winding angles and fibre types, to evaluate their mechanical performances and to perform damage analyses. In this context, glass, carbon and hybrid fibre reinforced composite pipes with ±25°, ±35° and ±45° winding angles were produced by filament winding method with 36 mm inner diameter and six layers. Fibre volume fractions (Vf) were determined by burning tests in accordance with ASTM D2584 standard. In order to investigate the mechanical behaviour of the composite pipes, ring tensile test according to ASTM D2290 standard, radial compression test according to ASTM D2412 standard and torsion tests according to ASTM D5448 standard were applied. Three repetitions were performed for each configuration in ring tensile tests, and analyses were made in accordance with the force-strain and stress-strain curves obtained. After the tests, the damaged specimens were analysed with high resolution images at macro scale and stereo microscope at micro scale. In radial compression tests, force-length behaviour was evaluated by applying loading up to 70% of the inner diameter of the pipes. For torsion tests, 500 mm long specimens were prepared by adhesive bonding method, tests were carried out in the relevant laboratory environment and torque-torsion angle and stress-strain data were analysed. Damage analyses were detailed using scanning electron microscopy (SEM) as well as macro observations. According to the results obtained, hybrid fibre reinforced composite pipes with ±45° winding angle were found to exhibit the highest performance in terms of bearing capacity, energy absorption capability and damage management.