Incremental constitutive models for elastoplastic materials undergoing finite deformations by using a four-dimensional formalism

摘要

When constructing incremental constitutive models of elastoplasticity for materials undergoing finite deformations, the tensors and their rates should respect the principle of frame-indifference. Instead of classical 3D approaches in which different objective transports may be arbitrarily used in the constitutive equations, we propose to model the constitutive equations using the four-dimensional formalism of the theory of Relativity. This formalism ensures that any 4D tensor is frame-indifferent thanks to the principle of covariance. It is further possible to define 4D rate operators that are all, by construction, frame-indifferent. Among these covariant rates, the 4D Lie derivative is chosen to construct incremental constitutive relations because it is invariant to the superposition of rigid body motion. A 4D rate type model of elastoplasticity with isotropic hardening is thus developed and compared with existing classical 3D constitutive models of elastoplasticity established in the context of finite deformations. (C) 2016 Elsevier Ltd. All rights reserved.