Celia Reina, Landry Fokoua Djodom, Michael Ortiz and Sergio Conti Kinematics of elasto-plasticity: Validity and limits of applicability of $F=F_eF_p$ for general three-dimensional deformations Journal of the Mechanics and Physics of Solids, 121: 99--113 2018 10.1016/j.jmps.2018.07.006
2017
Celia Reina and Sergio Conti Incompressible inelasticity as an essential ingredient for the validity of the kinematic decomposition $F=F^eF^i$ J. Mech. Phys. Solids, 107: 322--342 2017 10.1016/j.jmps.2017.07.004
2016
Celia Reina, Anja Schlömerkemper and Sergio Conti Derivation of $\bf F=\bf F^\rm e\bf F^\rm p$ as the continuum limit of crystalline slip J. Mech. Phys. Solids, 89: 231--254 2016 10.1016/j.jmps.2015.12.022
2014
Celia Reina and Sergio Conti Kinematic description of crystal plasticity in the finite kinematic framework: a micromechanical understanding of F=F^e F^p J. Mech. Phys. Solids, 67: 40-61 2014 http://dx.doi.org/10.1016/j.jmps.2014.01.014
Abstract: The plastic component of the deformation gradient plays a central role in finite kinematic models of plasticity. However, its characterization has been the source of extended debates in the literature and many important issues still remain unresolved. Some examples are the micromechanical understanding of $F=F^eF^p$ with multiple active slip systems, the uniqueness of the decomposition, or the characterization of the plastic deformation without reference to the so-called intermediate configuration. In this paper, we shed some light to these issues via a two-dimensional kinematic analysis of the plastic deformation induced by discrete slip surfaces and the corresponding dislocation structures. In particular, we supply definitions for the elastic and plastic components of the deformation gradient as a function of the active slip systems without any a priori assumption on the decomposition of the total deformation gradient. These definitions are explicitly and uniquely given from the microstructure and do not make use of any unrealizable intermediate configuration. The analysis starts from a semi-continuous mathematical description of the deformation at the microscale, where the displacements are considered continuous everywhere in the domain except at the discrete slip surfaces, over which there is a displacement jump. At this scale, where the microstructure is resolved, the deformation is uniquely characterized from purely kinematic considerations and the elastic and plastic components of the deformation gradient can be defined based on physical arguments. These quantities are then passed to the continuous limit via homogenization, i.e., by increasing the number of slip surfaces to infinity and reducing the lattice parameter to zero. This continuum limit is computed for several illustrative examples, where the well-known multiplicative decomposition of the total deformation gradient is recovered. Additionally, by similar arguments, an expression of the dislocation density tensor is obtained as the limit of discrete dislocation densities which are well characterized within the semi-continuous model.