An accurate 3D-FE based radius prediction model for in-plane roll-bending of strip considering spread effects

How to precisely predict the radius of the formed ring part under various loading conditions has become a critical issue for guiding practical forming in the in-plane roll-bending of strip (IRS). Spread (increasing rate of strip width) induced by unequal deformation may have close relationship with the radius development in the nonlinear physical process. After the analytical and experimental analysis on the spread contribution to roll-bending, an elastic-plastic 3D-FE explicit model is established and validated to study the spread effects and the radius development. Combined with the experiments, the FE results are compared with the previous ones under the assumption of plane strain theory (without considering spread effects) to address their applicability in radius prediction. The results show that: (1) the established FE model is reliable to accurately predict the radius of the formed ring part under various loading conditions with precision improved by 56.5%; (2) for the aluminum AA-3003O 30 mm × 2 mm (width × thickness) strips, the previous plane strain models are acceptable to predict the radius only when the spread is in the range of 4-6% or even narrower range of 3.2-6% under various loading conditions by changing bite location and wedge angle.