Tensile Properties of CFRP and Hybrid FRP Composites at Elevated Temperatures

The performance of fiber reinforced polymer (FRP) composites at high temperatures is a serious concern that needs investigation before the incorporation of these composites into important engineering structures. This article presents an experimental study on the tensile properties of carbon fiber reinforced polymer (CFRP) sheets, hybrid carbon/glass fiber reinforced polymer (C/GFRP) sheets and hybrid carbon/basalt fiber reinforced polymer (C/BFRP) sheets at different temperatures. The specimens of FRP sheets were tested at temperatures ranging from 16 to 200 degrees C, while corresponding dry fiber sheets (without resin impregnation) were tested at 16 degrees C as a reference. The test results show that the tensile strength of carbon fibers in different FRP sheets decreases significantly with increasing temperature, and remains almost stable at an ultimate value (3000 MPa) after the polymer exceeds its glass transition temperature (T-g), which is higher than the tensile strength of the non-impregnated fiber sheets at room temperature. At elevated temperatures, the hybridization of fibers can reduce the scatter of the tensile strengths of CFRP composites. Additionally, the tensile strength of CFRP sheets with different dimensions is significantly different, but size dependence is independent of temperature. Furthermore, elevated temperature also influences the failure modes of FRP composites.