Determination of mechanical behaviors of filament wound hybrid composite pipes

This study investigates the effects of intraply fiber hybridization on mechanical properties of composite pipes fabricated by filament winding technique. For this purpose, a 2-axis automated filament winding machine has been designed and fabricated to prepare composite pipe samples. The samples were manufactured at 6 layers at three different fiber orientations (±(40°), ±(55°) and ±(70°)) in order to investigate the effect of hybridization more effectively, by following performance at different winding angles. Split-disk test as in ASTM D2290 was used to establish apparent tensile strength of the samples. Axial compression behaviors and stiffness characteristics of the samples were determined according to ASTM D695 and ASTM D2412, respectively. In addition, the samples were separately compressed in axial and lateral directions and the crushing behaviors were determined in these directions. Finally, ignition loss tests were carried out in accordance with ASTM D2584 to determine the fiber contents of the samples. Failure modes were examined for each test separately to understand the fracture mechanisms. Tensile test results showed that apparent tensile properties of non-hybrid composite pipes are better than those of hybrid composite pipes. The quasi-static compression performance of hybrid samples was found to be marginally different in axial and radial directions such as; inclusion of carbon fiber improved compression strength in the axial direction while leading decrease of pipe stiffness in the radial direction. Crushing procdure of hybrid composite pipes were seen as more stable and regular compared to non-hybrid ones. The overall performance of the hybrid composites were found to be in the range of the results of non-hybrid composite pipes.