LAUSR

Abstract In this paper, dispersion corrected density functional theory (DFT-D) is performed on the α-crystal phase of nylon-6, 6 as a reference case for comparison in order to develop a continuum-DFT model. The DFT-D model is subjected to 6 independent mechanical loadings and the anisotropic linear mechanical behavior of the material is surveyed. In order to develop the nonlinear anisotropic model, different hyperelastic anisotropic (HA) models are assessed in comparison with the DFT-D results. In this regard, the tensile stresses are applied on the DFT-D model step by step along the chain direction and the stresses and density of strain energies of the continuum model are compared with the DFT-D simulation results. Consequently, the nonlinear anisotropic mechanical properties are calculated based on the inverse optimized least square technique (IOLST). The results reveal that the appropriate HA modelling technique including generalized Neo-Hokean energy incorporated with Holzapfel-Grasser-Ogden anisotropic (HA-NHGO) model is well defined to predict the nonlinear anisotropic mechanical behavior of the nylon-6, 6 crystal phase.