A finite deformation gradient-enhanced damage model for nanoparticle/polymer nanocomposites: An atomistically-informed multiscale approach

To analyze the experimentally observed failure process in nanoparticle/polymer nanocomposites, a variety of factors, including nonlocal characteristics of damage mechanism and nonlinear viscoelasticity, are required to be investigated. This work presents the development and numerical implementation of a finite deformation gradient-enhanced damage model for boehmite nanoparticle (BNP)/epoxy nanocomposites. The parameters identification of the nonlocal constitutive description is realized using a framework based on molecular simulations and experimental tests. In this context, molecular simulations are performed to parameterize the Argon model of viscoelasticity, while damage and nonlocal parameters are determined using experimental data obtained from compact-tension tests. The nonlocal constitutive model integrated into a nonlinear FE analysis is validated by comparing the numerical results of compact-tension tests of BNP/epoxy samples with experimental data. The experimental-numerical validation confirms the predictive capability of the modeling framework. The proposed procedure can be extended to other types of nanoparticle reinforced thermosetting polymers.