Constitutive Equations for Hot Working

TLDR: In this paper, a set of internal variable type constitutive equations which model large elastic-viscoplastic deformations of metals at high temperatures is formulated, and the values for the material parameters appearing in these functions are determined.

Abstract: : A set of internal variable type constitutive equations which model large elastic-viscoplastic deformations of metals at high temperatures is formulated. For a first-order representation of large deformation constitutive behavior we use a scalar as an internal variable to represent the isotropic resistance to plastic flow offered by the internal state of the material. Hot compression tests on an iron-2% silicon alloy have been conducted. Based on these experiments, specific viscoplastic constitutive functions are proposed, and the values for the material parameters appearing in these functions are determined. The constitutive equations with these functions and material parameters accurately reproduce the basic tests and also accurately predict the response of the metal to some critical experiments which were not used to determine the material parameters in the constitutive functions. Keywords: Deformation; Strain(Mechanics); Stresses; Metals; Plastic properties; Strength (Mechanics); Time dependence; Strain rate; Environments.