Fracture properties prediction of clay/epoxy nanocomposites with interphase zones using a phase field model

We predict the macroscopic tensile strength and fracture toughness of fully exfoliated nano silicate clay epoxy composites accounting for the interphase behavior between the polymeric matrix and clay reinforcement. A phase field approach is employed to model fracture in the matrix and the interphase zone of the polymeric nanocomposites (PNCs) while the stiff clay platelets are considered as linear elastic material. The effect of the interphase zones, e.g. thickness and mechanical properties (Young's modulus and strain energy release rate) on the tensile strength, and fracture parameters of the composite is studied in detail. The dissipation energy due to fracture in the PNCs is extracted for different thicknesses and properties of the interphase zones. We show through numerical experiments that the interphase thickness has the most influence on the tensile strength while the critical strain energy release rate of the interphase zones affects the dissipation energy depending on the interphase zone thickness.