Fatigue failure behavior of glass/epoxy ±55 filament wound pipes under internal pressure

In this study, fatigue behavior of filament wound composite pipes under alternating internal pressure has been investigated. GRP pipes which made of E-glass/epoxy are tested under open ended conditions. Test specimens have four layers which have ±55° winding angle. Tests have been done in accordance with ASTM D-2992. This standards offers 0.42 Hz frequency and R = 0.05 stress ratio. Tests have been performed at different load levels from 30% to 70% of ultimate strength. Whitening, leakage and final failure levels of GRP pipes have been observed. Fatigue results are presented and interpreted by means of S-N curves.