Tensile strength retention of fibre-reinforced polymer composites exposed to elevated temperatures: A meta-analysis review

Understanding the tensile strength of fibre-reinforced polymer (FRP) at high temperatures is crucial for structural safety. FRPs exposed to elevated temperatures show minimal changes in mechanical properties until reaching the resin softening temperature (Ts), followed by a decline to a residual value (Presidual) at the resin melting temperature (Tm), with the decline past Ts indicating the resin's glass transition range (Tg). This review analyses 790 experiments on Tensile Strength Retention (TSR) of FRPs exposed to elevated temperatures. Various research studies have investigated the impact of parameters such as fibre and resin types, sample thickness, fibre orientation, exposure duration, cooling-off periods, and fibre-to-resin ratio on the TSR of FRPs under elevated temperatures. The results revealed that while factors like exposure time and fibre-to-resin ratio have marginal effects, others exhibit significant impacts. Researchers have developed predictive models, which are effective in accurately predicting the TSR but are limited to specific datasets, requiring frequent recalibrations when applied to different composites due to overlooking various influential factors. This ongoing need for calibration limits the generalisability of existing predictive models to other composite types. Developing a comprehensive predictive model considering these factors could reduce the need for extensive calibration when using new composite materials.