Effect of salt–fog spray environment on bending fatigue properties of 3D woven composites

In this study, the effect of salt–fog spray corrosion environment on bending fatigue properties of three-dimensional (3D) woven composites was investigated. Three test environmental conditions, namely a normal environment, two cycles of salt–fog spray corrosion environment, and four cycles of salt–fog spray corrosion environment, were designed. In addition, the salt–fog spray corrosion mechanism, the bending fatigue properties, damage mechanisms, and failure modes of 3D woven composites were studied. The results showed that the bending strength and bending modulus decreased by 5.5 and 9.3%, and 2.27 and 3.45% after two and four salt–fog spray cycles, respectively, compared with that of the normal environment. The bending fatigue properties of 3D woven composites were related to the applied stress and salt–fog spray cycles. The salt–fog spray environment was responsible for the degradation of the interface bonding strength. The maximum reduction ratio of bending fatigue life after salt–fog spray treatment exceeded 70%. The brittle fracture characteristics of 3D woven composite yarn were more pronounced with an increase in salt–fog spray aging cycles.