Determination of bending limit curves for aluminium alloy AA6014-T4: an experimental approach

The conventional forming limit curves as proposed by Keeler and Goodwin fail to evaluate formability in case of bending and hemming operations. This is due to the different failure mechanisms involved in biaxial forming and bending/hemming operations. To overcome this difficulty, concept of bending limit curve has been introduced. This work presents an experimental approach to determine the BLC for aluminium alloy AA6014-T4. AA6014-T4 was selected as the workpiece due to its extensive application in outer panels of car bodies. The bending samples were printed with speckle pattern and measurement of bending strain was carried out with the help of GOM Aramis software. The three point bend test was conducted with two punch radii of 0.4 mm and 2 mm to study the effect of punch radius on bending limit strains. The complete formability picture was obtained by plotting combined forming limit and bending limit curves.by Ipsita Madhumita Das, Krishna Kumar Saxena and Jyoti Mukhopadhya