Multi-objective optimization basing modified Taguchi method to arrive the optimal die design for CGP of AZ31 magnesium alloy

Magnesium alloy is one of lightweight structural metals possessing low density and excellent corrosion resistance, which has limited applications due to cold plastic processing ability. Material properties can be improved through constrained groove pressing (CGP) process. Corrugated dies are designed to examine the deformation of AZ31 Mg alloy samples. To minimize numerical simulations, Taguchi’s L₉ OA (orthogonal array) has been adopted for the grooved die dimensions such as groove angle, groove width and coefficient of friction. Elasto-plastic finite element analysis is carried out implementing a simple and reliable multi-objective optimization basing modified Taguchi approach for obtaining the optimal die geometry. Reduction in total deformation and increase in the equivalent stress as well as elastic strain of AZ31 sheet was possible with 50° groove angle, 3 mm groove width and 0.1 friction coefficient. Hence the proposed die design can be suitable for multiple CGP passes with improved deformation homogeneity in the pressed sheet. H13 steel is used as die material to perform simulations using ANSYS workbench.