The effect of stress ratio on the fracture morphology of filament wound composite tubes

A comparative study was done between two typical loading conditions (closed-end and restrained-end condition) in the pipeline and piping systems manufactured by filament wound composite tubes with the objective of studying the influence of loading condition on fracture morphology. Four thin-walled E-glass fiber epoxy tubes with different wind angles were produced to perform hydrostatic tests under restrained-end condition. The results were compared with composite tubes tested under closed-end condition in previous work. Unlined tubes were first tested to obtain the leakage failure and then tubes lined with PVC were tested for burst failure pressure under restrained-end condition. The results showed that the fracture morphology of filament wound composite tubes hold a direct relationship to the stress ratio (σHoop:σAxial).