Multi-scale analysis of the early damage mechanics of ferritized ductile iron

A multi-scale analysis of the linear elastic and the early damage stages of ferritic ductile iron is introduced in this work. The methodology combines numerical and experimental analyses in the macro and micro scales. Experiments in the micro-scale are used for the characterization of the material micro constituents and the assessment of the micro-scale damage mechanisms; experiments in the macro-scale provide the data to calibrate and validate the models. The 2D multi-scale problem is modeled using the pre-critical regime of the Failure-Oriented Multi-Scale Variational Formulation, which is implemented via a FE2 approach. Finite element analysis in the micro-scale is customized to account for plastic deformation and matrix-nodule debonding. The multi-scale model is found effective for capturing the sequence and extent of the damage mechanisms in the micro-scale and to estimate, via inverse analyses, parameters of the matrix-nodule debonding law. Results allow to develop new insights for the better understanding of the ductile iron damage mechanics and to draw conclusions related to the modeling aspects of the multi-scale simulation.