Identification of plastic constitutive parameters at large deformations from three dimensional displacement fields

• Published in: Computational mechanics Vol. 49; no. 1; pp. 53 - 71
• Main Authors: Rossi, Marco, Pierron, Fabrice
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.01.2012; Springer; Springer Nature B.V; Springer Verlag
• Subjects: Algorithms; Analysis; Artificial Intelligence; Classical and Continuum Physics; Computational Science and Engineering; Computer Science; Computer simulation; Displacement; Engineering; Engineering Sciences; Equilibrium equations; Finite element method; Identification methods; Inverse problems; Mechanics; Necking; Original Paper; Parameter identification; Plane strain; Plane stress; Plastic deformation; Plastic properties; Strain localization; Tensors; Theoretical and Applied Mechanics; Inelastic and finite deformation; Inverse methods; Constitutive modelling; Numerical algorithms; Inelastic and fi nite deformation
• ISSN: 0178-7675; 1432-0924; 1432-0924
• DOI: 10.1007/s00466-011-0627-0

The aim of this paper is to provide a general procedure to extract the constitutive parameters of a plasticity model starting from displacement measurements and using the Virtual Fields Method. This is a classical inverse problem which has been already investigated in the literature, however several new features are developed here. First of all the procedure applies to a general three-dimensional displacement field which leads to large plastic deformations, no assumptions are made such as plane stress or plane strain although only pressure-independent plasticity is considered. Moreover the equilibrium equation is written in terms of the deviatoric stress tensor that can be directly computed from the strain field without iterations. Thanks to this, the identification routine is much faster compared to other inverse methods such as finite element updating. The proposed method can be a valid tool to study complex phenomena which involve severe plastic deformation and where the state of stress is completely triaxial, e.g. strain localization or necking occurrence. The procedure has been validated using a three dimensional displacement field obtained from a simulated experiment. The main potentialities as well as a first sensitivity study on the influence of measurement errors are illustrated.