Flexural Properties of Carbon/Glass Hybrid Thermoplastic Epoxy Composite Rods Under Static and Fatigue Loadings

Cables are primarily used in structures as tensile elements, but they are also subjected to compressive, flexural, and shear loadings. Therefore, in addition to the hybrid rods’ tensile properties, the other corresponding mechanical properties must also be characterized. This study is an investigation of the flexural behavior of carbon/glass hybrid thermoplastic epoxy composite rods. Test results indicated that an increase in the void content to a decrease in the flexural strength, and consequently the Weibull modulus as well. The flexural fatigue performance (in terms of maximum stress) increases with the static flexural strength. The intercept for power law model increased with increasing carbon fiber volume fraction, and decreasing matrix content and void content. The absolute values of slope for power law model decreased with increasing carbon fiber volume fraction, and increasing matrix content and void content. The fatigue strength at 1 × 10⁷ cycles for the hybrid rods was less than 20–30% of the ultimate flexural strength. The static and fatigue flexural properties for the hybrid rods were strongly influenced by kinking, buckling, and delamination behaviors of unidirectional carbon fiber bundle composites.