Numerical modelling of aluminium sheets formability using response surface methodology

This study considers the tensile properties, formability limit strain and void coalescence parameters of the commercially available aluminium alloy sheets in metal forming processes using response surface methodology (RSM). Sheets of three different thickness were chosen for this study. The experimental procedure involved tensile test, forming test and void coalescence study. The effect of important input parameters namely sheet thickness, specimen orientation and annealing temperature (Heat Treatment) were used for the output of tensile test. On the other hand, the sheet thickness, blank width and annealing temperature were used for finding the output of formability cupping test. These input factors and corresponding output parameters were mathematically evaluated using Design Expert 8.0.7.1, trial software for constructing the numerical modelling on the output parameters namely strain hardening exponent (n-value), plastic strain ratio (r-value), strength coefficient (K-value), product of n-value and r-value (nr-value), fracture and forming limit strain and void coalescence properties like d-factor, ligament thickness, length to width (L/W) ratio and void area fraction.

► Higher annealing temperature improves the formability.
► The formability has been correlated with the numerical model.
► There is a good agreement between experimental results and predicted models.