Machining simulation of ductile iron and its constituents. Part I: Estimation of material model parameters and their validation

A microstructure-level simulation model was recently developed to characterize machining behavior of heterogeneous materials. During machining of heterogeneous materials such as cast iron, the material around the machining-affected zone undergoes reverse loading, which manifests itself in permanent material softening. In addition, cracks are formed below and ahead of the tool. To accurately simulate machining of heterogeneous materials the microstructure-level model has to reproduce the effect of material softening on reverse loading (MSRL effect) and material damage. This paper describes procedures used to calculate the material behavior parameters for the aforementioned phenomena. To calculate the parameters associated with the MSRL effect, uniaxial reverse loading experiments and simulations were conducted using individual constituents of ductile iron. The material model was validated with reverse loading experiments of ductile iron specimens. To determine the parameters associated with fracture of each constituent, experiments and simulation of notched specimens are performed. During the validation stage, response of simulated ductile iron was in good agreement with the experimental data.