On The Role of Constitutive Modeling and Computational Parameters in the Numerical Simulation of Dynamic Tensile Extrusion Test

In Dynamic Tensile Extrusion (DTE) test, the material is subjected to extreme conditions, such as severe plastic deformations, high pressures, and large variations of temperature and strain rate. Although the numerical simulation of this test is ideal for constitutive model validation, there are several computational features to assess before performing further analyses. This work aims to evaluate the influence of constitutive modeling and computational parameters on the predicted material jet in the simulation of DTE tests on Oxygen-Free High Conductivity Copper at different extrusion velocities. Dynamic transient analyses have been performed with implicit finite element code using a single-step Houbolt procedure. To begin with, three constitutive models (the Mechanical Threshold Stress, modified Johnson–Cook, and Zerilli-Armstrong) were selected and model parameters have been identified on available uniaxial tensile test data at different temperature and strain rates. Successively, the effect of friction, damping, remeshing, and extrusion die modeling has been investigated by performing parametric numerical simulations at 400 m/s extrusion velocity and an optimum set of computational parameters was determined. Finally, constitutive models' performance has been verified by comparing the predicted size, shape, and number of extruded fragments at different velocities with experimental data. The ability to correctly predict the size and shape of the last temporally forming fragment appears to be directly related to the ability of the constitutive model to accurately describe the material response in the viscous drag regime.