Hemming is a manufacturing process to fold a sheet onto itself or another sheet. The dimensional defects (roll-in/rollout, warp/recoil, distortion due to springback, etc.) of hems critically impact the perceived quality of automotive exteriors. This paper summarizes the procedures and the results of three-dimensional (3D) numerical simulations on curved edge-curved surface hemming of aluminum alloy AA6111-T4PD. A solid-element model is built in ABAQUS using explicit quasi-static finite element (FE) procedure for flanging, pre-hemming and final hemming, and implicit procedure for the corresponding preloading and resulting springback at high simulation cost. Aiming at improving the computational efficiency, various approaches have been taken and tested including using shell elements as alternatives, developing simplified simulation procedure by combining pre- and final hemming in explicit scheme, and further simplification by neglecting intermediate springback analysis. The same conditions are analyzed using shell elements in LS-DYNA, but only final hemming springback is considered. The results of the simplified models are compared with the results of ABAQUS solid-element model with complete procedure. Both accuracy and efficiency of the models are presented and discussed.

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