Characterization of Energy Dissipation in Fiber/Matrix Composites under Transverse Tension

Abstract

Cohesive zone elements were used to model diffuse cracking and the eventual formation of a dominant crack in fiber/matrix composites under transverse tension. The effect of the fiber/matrix interfacial and matrix strengths on the overall RVE behavior was studied using an ensemble of random realizations. The RVE strength was slightly more sensitive to a change in the matrix strength compared to the fiber/matrix interfacial strength and was significantly more sensitive to a decrease in either constituent strength compared to an increase because the transverse tensile strength of the composite is more dependent on the weaker constituent. The energy dissipated by diffuse damage and along the dominant crack was separated, and the effect of the microscale strengths on the energy dissipation was studied. Although varying the microscale strengths changed the ratio of the energy dissipated diffusely versus along the dominant crack, the total energy dissipated was insensitive to the changes in the microscale strengths, except when increasing the matrix strength, which resulted in an overall increase in energy dissipated. The energy dissipated within each cohesive zone was visualized for the load increments just before the dominant crack formed and well after the dominant crack formed. The location of the dominant crack was related to the intensity and arrangement of diffuse damage within the RVE, but further research is needed to understand the relationship well. Tracking the diffuse damage and dominant crack separately, using an ensemble of realizations to predict statistically significant results, and visualizing the energy dissipated within the RVE were shown to be useful for understanding progressive failure when significant diffuse damage exists.