Modeling of anisotropic inelasticity in pearlitic steel at large strains due to deformation induced substructure evolution

A macroscopic model for deformation induced anisotropy due to substructure evolution at large strains in pearlitic steel is proposed within a thermodynamically consistent framework. The model is motivated via experimental observations, e.g., [Ivanisenko, Y., Lojkowski, W., Valiev, R.Z., Fecht, H.-J., 2003. The mechanism of formation of nanostructure and dissolution of cementite in a pearlitic steel during high pressure. Acta Mater. 51, 5555-5570]. Although each pearlitic grain has a preferred direction determined by cementite lamellas, initial random orientation of the grains is interpreted as initial macroscopic isotropy. However, the oriented grains tend to align after large shear deformation. The proposed model for evolution of orientation and stiffness is inspired by recent developments in bio-mechanics, e.g., [Imatani, S., Maugin, G.A., 2002. A constitutive model for material growth and its application to three-dimensional finite element analysis. Mech. Res. Commun. 29, 477-483; Menzel, A., 2004. Modelling of anisotropic growth in biological tissues. Biomech. Model. Mechanobiol. 3, 147-171]. One important application is large irreversible shear deformations in the surface layer of railway track components.