Numerical Analysis of Plastic Strain Inhomogeneity in Rectangular Vortex Extrusion (RVE) Process

In this study, the effect of geometrical parameters of rectangular vortex extrusion die, including twist angle (𝜑), reduction in area (𝑅𝐴), and twist zone length (𝐿), on deformation inhomogeneity is investigated using the finite element analysis and response surface methodology. Analysis of variance (ANOVA) was used to determine the primary parameters and accuracy of the mathematical model obtained from response surface methodology results. The results showed that the suggested mathematical model predicts the strain inhomogeneity with high accuracy. Additionally, it revealed that the input parameters of 𝜑, 𝑅𝐴, 𝐿, the interaction between 𝜑 and 𝑅𝐴 (𝜑 × 𝑅𝐴), and interaction between 𝑅𝐴 and 𝐿 (𝑅𝐴 × 𝐿) are the main significant factors affecting the inhomogeneity. Perturbation plots and 3D surface diagrams were used to check the results of ANOVA, the sign, and the magnitude of the coefficient of the suggested mathematical model.