Özet:

The stress and strain behaviors of filament wound glass-fiber epoxy based cylindrical tube structures made of two different stacking sequences as [(±45°)5] and [(0/ 90)5] were numerically investigated under a constant torque value. The exterior surfaces of tubes were deliberately defected by longitudinally extending, rounded end, 0.6 mm deep, 2 mm wide but varying-length slots. Slot-less and full-length-slot structures were also included in the study. During torsional loading, the variations in stresses, strains and twisting angles of the specified thin-walled composite tube models were investigated, comparatively. Additionally, the effects of fiber winding angles and slot lengths on the specified quantities were parametrically examined. A considerable amount of stress accumulation around the slot tip of both type of tube model is measured which constitute a risk of damage progression. At the innermost laminas, slight fluctuations in the maximum stresses are observed in the slot lengths shorter than 140mm, whereas rapid increases are remarkable for exceeded lengths. On the other hand, the maximum stress changes in the outermost layer are quite uneven. From slot-less to full-length-slot, the change in slot dimensions provokes 8.32 and 9.11 % increments in twisting angles in the 45°/-45° angle-ply and 0°/90° cross-ply structures, respectively. Under the same loading condition, [(±45°)5] stacking sequence gives the structure averagely 0.66° lower total rotation at the specimen tip in comparison to [(0/ 90)5] fiber arrangement.

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