Prediction of strength degradation of glass fiber under water environment using sub-critical crack growth model

The mechanical properties of FRP are mainly dominated by the fiber-reinforcement and therefore practically influenced by the strength degradation of the glass fiber. In this paper, the strength degradation of embedded E-glass fiber in the single fiber composite (SFC) has been investigated under constant strain in water environment to represent the SCC of GFRP. The strength degradation of the embedded glass fiber was ascertained by fragmentation test after the constant strain test. It was clarified that the fiber strength degradation was to accelerate dramatically at elevated water temperature. Additionally, the degradation of the glass fiber strength has been quantified on the basis of microscopic SCC of the initial defects on the fiber surface using the sub-critical crack growth model. The proposed model showed good agreement with the fiber strength distribution from various experimental results.