A finite deformation phase-field fracture model for the thermo-viscoelastic analysis of polymer nanocomposites

Abstract

The prediction of failure processes in polymer nanocomposites requires accurately capturing different factors such as damage mechanisms, and temperature- and rate-dependent material characteristics. This work presents the development of a finite deformation phase-field fracture model to analyze the thermo-viscoelastic behavior of boehmite nanoparticle/epoxy nanocomposites. To characterize the rate-dependent fracture evolution, the free energy is additively decomposed into an equilibrium, a non-equilibrium, and a volumetric part with a varying definition under tensile and compressive deformation. Furthermore, the Guth–Gold and modified Kitagawa models are adopted to consider the effect of the nanoparticle contents and temperature on the nanocomposites’ fracture behavior. The applicability of the proposed model is evaluated by comparing the numerical results of compact-tension tests with experimental data. The experimental–numerical validation justifies the predictive capability of the model. Numerical simulations are also performed to study the effect of temperature and deformation rate on the force–displacement response of boehmite nanoparticle/epoxy samples in the compact-tension tests.