Fatigue degradation and life prediction of basalt fiber-reinforced polymer composites after saltwater corrosion

This paper describes the degradation of the tension-tension fatigue behavior of basalt fiber-reinforced polymer (BFRP) composites after exposure to a salt solution. Two levels of stress ratio (R = 0.1 and 0.8) were applied to typical fatigue applications during the experiment. The stiffness degradation and S-N curves of the specimens for different durations of aging were recorded. The damage evolution and fracture surface of aged and non-aged specimens were also recorded during fatigue loading using in-situ scanning electron microscopy (SEM). The results show that the static strength of the BFRP shows negligible degradation after aging in the salt solution, whereas the detrimental effect of saltwater becomes apparent under fatigue loading. From the SEM images of fatigue damage for different aging times, it can be seen that the fiber/matrix interface region becomes a controlling factor in the fatigue behavior with early interface debonding occurring in the aged specimens. The interface deteriorates with respect to the aging time and lower stress ratio, which results in different fatigue lives and degradation properties of BFRP composites after saltwater corrosion. The fatigue life prediction indicates that the fatigue strength of BFRP degrades to an acceptable level after the occurrence of saltwater corrosion.