An experimental study of the in-plane stretching of sheet metal

Experimental results are presented of the limit strains for the in-plane stretching of steel, aluminium and brass sheets. The development of surface strains is studied in incremental tests and attention is drawn to “crazing” of the surface of sheet specimens and to “banding” in aluminium specimens. Despite the wide difference in the mechanical properties of the three materials the values for the limit strain are remarkably similar. For steel and aluminium the limit strains are greater than the predicted instability strains, but for brass the limit strains are considerably less than the predicted instability strains. The wide scatter in the experimental limit strains perhaps indicates that failure is largely influenced by random effects.