Short-term tensile creep behaviour at elevated temperature of GFRP laminates produced by vacuum infusion

The fire performance of fibre-reinforced polymer (FRP) composites is a critical issue. Elevated temperatures degrade their short-term mechanical properties and also affect their viscoelastic behaviour. While both these aspects need to be duly considered in the design of FRP structures, little is known about the time-dependent mechanical properties of FRP materials at ET. To address this knowledge gap, this paper presents an experimental and analytical study on the effect of elevated temperature on the short-term (up to 3 h) tensile creep behaviour of glass-FRP (GFRP) laminates produced by vacuum infusion. Specimens were simultaneously subjected to elevated temperatures (from 20 °C to 300 °C, under steady-state conditions) and tensile loads (15% to 25% of their strength at room temperature). Tensile creep was observed to increase with temperature: (i) up to 100 °C, the creep coefficient increased by about 6 times and this behaviour was attributed to the glass transition process, which is associated with an increase in viscoelasticity; (ii) at higher temperatures, this effect was mitigated, and at 300 °C the creep coefficient was only around the double of that observed at room temperature. The suitability of analytical creep models to describe the short-term creep behaviour at ET was assessed. These models were found to be appropriate. Finally, predictive models were proposed to describe the evolution of the creep (power law) parameters with temperature.