Influence of hydrothermal ageing on the compressive behaviour of glass fibre/epoxy composite pipes

The effects of hydrothermal ageing on the crushing behaviour of glass fibre-reinforced epoxy (GRE) pipes are discussed. Pipes with three different winding angles (±45°, ±55°, ±63°) were manufactured by filament winding process. The pipes were then hydrothermally aged in tap water at a constant temperature of 80 °C for periods of 500, 1000, and 1500 h. Uniaxial compressive tests were conducted on the virgin and aged samples using a universal testing machine in accordance with ASTM D695-10. The tests were also performed at temperatures ranging from room temperature (RT) at 25 °C to 45 °C and 65 °C to study the response of the pipes at elevated temperatures. Scanning electron microscopy (SEM) images were captured and the relationship between the ageing period and strength of the GRE pipes was determined. The results indicate that the strength of the GRE pipes significantly decreases with increase in the temperature and ageing period. On the contrary, the strength increases as the winding angles decrease. The compressive strength of the pipes was also predicted using a Berbinau's based model and was found to correlate well with the earlier obtained experimental results yielding a maximum variation of less than ∼25%.