Designing composite-based cylindrical structures and manufacturing composite prototypes by filament winding method

This study reports the design, finite element modeling, optimization, fabrication and testing of relatively thick (radius/thickness ~ 7) and long carbon fiber reinforced polymers produced by filament winding against buckling damage under axial loading. The optimum winding angle and stacking sequence against Linear (Eigenvalue) buckling were determined in accordance with the predetermined design requirements utilizing genetic algorithm (GA) optimization via MATLAB. During the optimization process, the critical buckling load factor (»cr) was assigned as objective function, design constraints were natural frequency (fn) and angle of twist (§), and ply angles were considered to be variable and restricted with 20 to 87-degree continuous fiber angles in the laminate sequences. As a consequence of the test results, »cr of the proposed optimum model was found to be 3.2 times better than the reference model and both the analytical and finite element model satisfactorily predicted the critical buckling load for all CFRP rods consistent with the test results. The critical buckling loads calculated by applying a KDF of 0.95 for the finite element model and a KDF of 0.9 for the analytical solution were found to be reasonably appropriate for use in the preliminary design input. Additionally, results showed that a higher axial to the circumferential ratio of axial and bending stiffness (A11/A22, D11/D22) promises better buckling performance than other possible candidates. Finally, the microstructures of the produced rods were examined and the fiber volume ratios were calculated by means of chemical characterization.