Characterization of machining of AISI 1045 steel over a wide range of cutting speeds. Part 2: Evaluation of flow stress models and interface friction distribution schemes

Abstract

To ensure that the simulation of the orthogonal metal-cutting process yields accurate results, the material and frictional behaviours during simulation have to be defined accurately. Flow stress models are used extensively in the simulations of deformation processes occurring at high strains, strain rates, and temperatures. In this work, the Johnson-Cook, Maekawa et al., Oxley, El-Magd et al., and Zerilli-Armstrong flow stress models are evaluated. AISI 1045 steel is used as the workpiece material because it is well characterized. First, the predictive capability of these flow stress models is compared with the published experimental data at high strain rates and the modelling errors are quantified. Different friction conditions along the tool rake face are also discussed. Then the friction conditions based on results of scanning electron microscopy-energy-dispersive X-ray analysis from Part 1 are implemented together with other friction models. The material flow stress models and friction conditions are assessed using an updated Lagrangian finite element code simulating continuous chip formation over a range of cutting speeds. The assessment of these models is carried out for their accuracy in predicting the cutting force and shear angle with those obtained experimentally in order to draw conclusions regarding their comparative performance.