Earing prediction performance of homogeneous polynomial-based yield function coupled with the combined hardening model for anisotropic metallic materials

Authors : Toros Arda Akşen, Murat Özsoy, Mehmet Fırat

Pages : 1-9

View : 174 | Download : 191

Publication Date : 2024-02-29

Article Type : Research Paper

Abstract :In the cup drawing process, the tensile stress in the radial direction is dominant during the drawing. However, the sheet bends around the punch and die radiuses, and the fibers touching the punch and die are exposed to compression, while the outer surfaces are exposed to tension. Therefore, the stress state at the radius regions of punch and die becomes complicated to overcome due to the bending and may influence the final earing form. The present study investigates the influence of a plasticity model involving an advanced yield criterion coupled with a combined hardening model on the earing prediction in the cup drawing process of AA6016-T4 aluminum alloy. Therefore, isotropic hardening and combined hardening models are implemented, respectively so as to show the kinematic hardening effect on the earing prediction performance. The combined hardening model comprises Armstrong-Frederic kinematic hardening and isotropic hardening rules together to characterize the hardening behavior of the sheet, and the parameters of the hardening model were obtained by considering a reversal shear test. A sixth-order polynomial-based yield criterion was implemented to represent the anisotropic response of the sheet successfully. The Hill48 yield criterion was also considered in the present study for comparison purposes. The analyses were conducted based on the additive plasticity approach and using the implicit stress update scheme in Marc commercial software. The punch force-displacement responses and earing profile predictions were obtained numerically and compared with the experimental outcomes. It was seen that introducing the combined hardening model enhances the earing prediction capability for both yield criteria. With the incorporation of the combined hardening rule, the improvement in the prediction of the earing profile was more apparent in HomPol6 results compared to Hill48. The HomPol6 yield criterion coupled with the combined hardening rule led to a better agreement in the prediction of ear formation.
Keywords : Kap çekme, Kulaklanma, Kinematik pekleşme, Plastisite