Microstructures failure analysis of fiber reinforced composites with various void types

Void defects in the matrix and between fibers inevitably occur during fabricating of fiber reinforced composites. Although the effects of matrix voids or interfiber voids on the properties of composites have been studied recently, the failure mechanisms and the damage evolution of composites with matrix voids and interfiber voids are still challenging to explore. The coupling effect between matrix voids and interfiber voids is also unclear. This work established three-dimensional parametric microstructure models simultaneously containing matrix voids and interfiber voids. The effects of void types and void volume fractions on the strength of composites are investigated quantitatively by the computational model. The damage evolution process is visualized, and the failure mechanisms and the coupling effect between various voids are explained on the microscale. Additionally, the failure envelopes of composites with different void volume fractions are provided in τ_13-σ_22 stress space, which has good agreements with both the Hashin–Rotem and Puck failure criteria. The verified computational model composed of the microstructure model and the failure envelopes can help designers accurately and conventionally predict the properties of composite materials in engineering.