A study on the buckling behaviour of aluminium alloy sheet in deep drawing with macro-textured blankholder

In this paper an experimental, numerical and analytical investigation is presented of the wrinkling behaviour that occurs in the flange of deep drawn cylindrical cups of aluminium alloy sheet using macro-textured blankholder surfaces. A series of deep drawing experiments were performed using a range of tool textures, draw ratios and blank-holding forces. A numerical material and process model was formulated to enable the occurrence of wrinkling to be simulated. In addition, two analytical buckling models of aluminium alloy sheet in deep drawing with macro-textured blankholder based on the energy method, (namely a one-dimensional and two-dimensional model) were developed for the first-time and utilised to predict the effect of process parameters on wrinkling. The analytical buckling models investigated two boundary conditions, hinged and built-in boundary condition. It was found that texture geometry and draw ratio had a significant effect on wrinkling but the blank-holding force did not. The analytical models developed in this paper to represent sheet metal wrinkling behaviour for the macro-textured tools can be used as a design guide to determine the geometry of tool textures necessary to avoid wrinkling defects in aluminium alloy stamping processes.