Failure analysis of syntactic foams: A computational model with cohesive law and XFEM

The interface debonding and damage progression from voids in glass/epoxy syntactic foams are two of the most common types of detrimental processes that have significant negative impact on the composites strength. In this paper, the effects of these progressive damage processes on the mechanical properties of syntactic foams are numerically investigated using a micromechanical approach. In particular, the tensile strength as a function of the interface properties and voids content of syntactic foams has been analyzed in detail using axisymmetric computational models with explicit consideration of the matrix cracking and the interface debonding, which are modeled using the Extended Finite Element Method (XFEM) and the cohesive zone method (CZM), respectively. The numerical results agree well with the available experimental data. Further parametric studies show that the interface properties play a major role in the failure behavior of syntactic foams, while the voids can reduce their tensile strength. In addition, the tensile strength decreases with the volume fraction of hollow particles, but increases with the particle shell thickness.