Abstract: In order to study the tensile fatigue properties of basalt fiber (BF) reinforced epoxy unidirectional composites at different ambient temperatures, a series of experimental tests and life prediction were carried out. Firstly, the maximum failure stress σ_m at room temperature was obtained by static tensile test. Then, the tension-tension fatigue tests with stress levels of 75%σ_m, 70%σ_m, 65%σ_m and 60%σ_m were carried out at three ambient temperatures (room temperature, 50 ℃, and 70 ℃), respectively, and the corresponding fatigue life cycles and obtained relevant fatigue stiffness data were achieved at different stress levels. Finally, the fatigue life at different ambient temperatures were estimated according to the exponential S-N curve. The results show that the fatigue life of basalt fiber composite increased with the decrease of stress level under the same temperature. The fatigue life decreased significantly with the increase of temperature under the same stress level, and the fiber-drawing of fatigue fracture increased dramatically with the increase of temperature. In the initial stage of tension-tension fatigue, the higher the temperature, the more obvious the stiffness degradation and the greater the degradation rate. The comparison analysis show that the fatigue properties of basalt fiber composites is better than that of glass fiber composites at room temperature.

Key words: unidirectional basalt fiber composites, temperature environment, tension-tensile fatigue, S-N curve, life prediction