Using DIC-based FEM to determine work-hardening parameters in structural steels

Abstract Optical measurement techniques are essential tools in materials testing for acquiring non-intrusive, full-field data. Traditionally, constitutive parameters have been derived from point-wise measurements. However, full-field measurements of kinematic fields open for extracting more comprehensive datasets. In this study, an approach that integrates digital image correlation (DIC) with the finite element method (FEM) is applied to identify work-hardening parameters from simple mechanical tests. In the proposed approach, the nodal displacement increments and the finite element (FE) mesh are provided by a two-dimensional DIC analysis of the mechanical test. They are then combined with a constitutive model to compute the stresses and nodal forces. The material parameters are subsequently determined by minimizing the difference between the global force–displacement curve calculated through the DIC-based FEM approach and the one measured in the experimental test. The method is applied and validated for three standard steels (Domex 240YP, Domex 490XP, and S355MC). DIC-based FEM is found to be an efficient alternative to traditional inverse methods for determining work-hardening parameters from tests involving simple geometries.