PARAMETERS DETERMINATION OF YOSHIDA UEMORI MODEL THROUGH OPTIMIZATION PROCESS OF CYCLIC TENSION-COMPRESSION TEST AND V-BENDING SPRINGBACK

Abstract

IN RECENT YEARS, THE STUDIES ON THE ENHANCEMENT OF THE PREDICTION CAPABILITY OF THE SHEET METAL FORMING SIMULATIONS HAVE INCREASED REMARKABLY. AMONG THE USED MODELS IN THE FINITE ELEMENT SIMULATIONS, THE YIELD CRITERIA AND HARDENING MODELS HAVE A GREAT IMPORTANCE FOR THE PREDICTION OF THE FORMABILITY AND SPRINGBACK. THE REQUIRED MODEL PARAMETERS ARE DETERMINED BY USING THE SEVERAL TEST RESULTS, I.E. TENSILE, COMPRESSION, BIAXIAL STRETCHING TESTS (BULGE TEST) AND CYCLING TESTS (TENSION-COMPRESSION). IN THIS STUDY, THE YOSHIDA-UEMORI (COMBINED ISOTROPIC AND KINEMATIC) HARDENING MODEL IS USED TO DETERMINE THE PERFORMANCE OF THE SPRINGBACK PREDICTION. THE MODEL PARAMETERS ARE DETERMINED BY THE OPTIMIZATION PROCESSES OF THE CYCLING TEST BY FINITE ELEMENT SIMULATIONS. HOWEVER, IN THE STUDY BESIDES THE CYCLING TESTS, THE MODEL PARAMETERS ARE ALSO EVALUATED BY THE OPTIMIZATION PROCESS OF BOTH CYCLING AND V-DIE BENDING SIMULATIONS. THE SPRINGBACK PREDICTIONS WITH THE MODEL PARAMETERS OBTAINED BY THE OPTIMIZATION OF BOTH CYCLING AND V-DIE BENDING SIMULATIONS ARE FOUND TO MIMIC THE EXPERIMENTAL RESULTS IN A BETTER WAY THAN THOSE OBTAINED FROM ONLY CYCLING TESTS. HOWEVER, THE CYCLING SIMULATION RESULTS ARE FOUND TO BE CLOSE ENOUGH TO THE EXPERIMENTAL RESULTS.