Shear Response of Glass-Fiber Reinforced Unidirectional Composites at Low Temperature

Glass fiber reinforced polymer (GFRP) laminates are candidate materials for application in many industrials especially aerospace; and this has induced the need for a proper knowledge of low temperature behavior of them. In this paper, the effect of low temperature on mechanical response of unidirectional (UD) glass-fiber composites under static shear loading is investigated by applying several experimental tests. The modified three-rail shear specimens equipped by electric strain gauges were used. Low temperature conditions were performed using an environmental test chamber which was able to cool down temperature simultaneously with mechanical tests in the range of -60 °C to 23 °C. The results of the present study indicate that the laminates under in-plane shear loading behave highly nonlinear for all temperature tests until final failure which is thought to be the result of micro-crack accumulation throughout the matrix. Also low temperatures have a significant effect on composite failure mode. It is also found that the strength and modulus of UD composites both increased with decreasing the temperature in shear loads. On the other hand, the results show that strain to failure decreased by decreasing the temperature.