Tool-based inverse determination of material model of Direct Aged Alloy 718 for FEM cutting simulation

Abstract

Direct aged Alloy (DA 718) has been widely used for aircraft engine components. FE-simulation of the cutting process of DA 718 can predict the process reliability regarding to the cutting force and the temperature. However, obtaining material and friction model for cutting simulation is still a challenge due to high strain, strain rate and temperature in shear zone. In this paper, a Coupled Eulerian-Lagrangian (CEL) FE-model has been applied to predict the cutting force and chip form in orthogonal cutting of DA 718. In order to obtain the material and friction model for the FE-model, an approach for inverse determination of the Johnson-Cook (JC) material model and the temperature-dependent friction model was applied. A software tool was programmed with Matlab to automatize this approach. By means of this software tool, experimental and simulative investigations of the friction behavior between carbide tool and DA 718 were conducted on a test bench on a broaching machine. A temperature-dependent friction model in tool-chip interface was determined. The parameters of the JC-material constitutive law and the JC-damage model were inverse determined by comparison of experimental and simulative results of cutting force, chip compression ratio and serration ratio in orthogonal cutting of DA 718. The FE-model with determined material and friction model was validated at different cutting speeds and feed rates with respect to cutting force and chip forms in orthogonal cutting.