| ABSTRACT |
Glass Fibre Reinforced Epoxy (GRE) composite tubes have wider appliance in oil and gas industry. The major advantage using composite structures is their durability and strength. The research is an attempt to study the performance behaviour of composites under various stress ratios and winding angles. Helically wound glass reinforced epoxy composite tubes of different winding angles (±45I0;, ±55I0;, and ±63I0;) are designed from AMREC, SIRIM. An automated novel test rig to perform Ultimate Elastic Wall Stress (UEWS) test is fabricated using Rotex make solenoid valves controlled using NI DAQ and Labview interface. The test rig is based on the internationally recognized standard ISO 14692 for GRE pipes through ASTM D2992 document. The test rig is capable of testing five stress ratios by a combination of internal pressure and axial loadings. [Pure axial (0H : 1A), hoop to axial (1H : 1A), pure hydrostatic (2H : 1A), quad hoop to axial loading (4H : 1A) and pure hoop (1H : 0A)]. The composite tubes are subjected to short term cyclic UEWS tests under various stress ratios and the UEWS failure points are determined based on the stress-strain response. The tubes are further tested until the weepage failure occurs. The failure envelope for different stress ratios are mapped and the effect of winding angles are investigated. The results are associated with ASTM D2992 type of regression testing for the determination of long term strength of composite pipes.
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