Determination of damage model parameters using nano- and bulk-scale digital image correlation and the finite element method

In this study, the nano-to bulk-scale fracture behaviors of a dual phase (DP) steel were investigated by combining a micro-digital-image-correlation (micro-DIC) technique and the finite element method (FEM). The emergence of surface cracks and nano-to bulk-scale strain distributions during plastic deformations were investigated using micro-DIC and macro-DIC techniques. FEM simulations were conducted to calculate the stress state of the damaged regions that could not be directly obtained from experiments. By combining nano-and bulk-scale observations, fracture strain and stress triaxiality of both scales were determined into model parameters for predicting the material damage behavior. The ac-curacy of the present damage model parameters was confirmed by comparing the load-displacement curves obtained from experimental result and proposed method. This new strategy of combining micro-scale deformation behavior and bulk-scale damage analysis facilitates defining damage model parameters through observing a wide range of regions with only one or two specimens, which is opposed to the conventional method that requires bulk-scale observations in multiple loading condition.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).