Experimental evaluation of wrinkling limit diagrams for aluminium alloy 5052 sheets annealed at different temperatures

The sheet-metal-forming operations are principal processes in the automotive industry. Aluminium alloy 5052 sheet is a widely used material in the automotive industry. With the aim of finding the safe working strains for this metal under various forming processes, a set of wrinkling limit diagrams in terms of strain and strain increment ratios and a forming limit diagram with a wrinkling limit curve superimposed have been constructed for the same sheet metal with 2.0 mm thickness annealed at four different temperatures. It has been found that the onset of wrinkling takes place when the ratio (der/deθ) of strain increments or the ratio (er/eθ) of strain reaches a critical value during the drawing process. Further it was observed that, the higher the annealing temperature, the greater was the safe strain region, because of higher normal anisotropy and strain hardening index values.