Plastic anisotropy effect on forming kinematics of the hole-flanging process

Abstract

The plastic anisotropy effect on the forming kinematics of the hole-flanging process was experimentally and numerically analyzed. Firstly, the heterogeneity of the flange thickness and the flange height along the circumferential direction were distinguished experimentally. The measurements were performed from different flanges obtained under various process conditions. In order to explain the experimental results, a 3D finite element model was developed for the different conditions. The zone of the flange in contact with the punch and the zone free from any contact with the tools were distinguished for hole-flanging both with and without ironing. The variation of the contact zone with the punch and the normal contact force were identified along the circumferential direction for selected punch displacements. The profiles of deformed flange obtained on rolling and transverse directions were also characterized. The dependence to the sheet orientation of the clearance thickness ratio (Rcc) which indicates the occurrence of ironing was finally studied. Accordingly, the experimental observations were justified. In some cases, numerical results were validated by experiments. A 0.8-mm 1000 series aluminum alloy was used as typical material.