Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Makina Mühendisliği Bölümü, Türkiye
Tezin Onay Tarihi: 2011
Öğrenci: MERİÇ UÇAN
Danışman: HALUK DARENDELİLER
Özet:This study focuses on the effects of different constitutive models in sheet metal forming operations by considering the cylindrical and square cup drawing and V-bending simulations. Simulations are performed using eight different constitutive models; elastic plastic constitutive model with isotropic hardening, elastic plastic constitutive model with kinematic hardening, elastic plastic constitutive model with combined hardening, power law isotropic plasticity, piecewise linear isotropic plasticity, Barlatthree-parameter, cyclic elastoplastic and Hill’48 model.The numerical analyses are accomplished by using three different 1 mm thick sheet materials; St12 steel, Al-5182 aluminum and stainless steel 409 Ni. An explicit finite element code is used in the simulations. For square cup drawing, three different blank holder forces; 2 kN, 4 kN and 5 kN are considered for St12 steel, whereas only 5 kN blank holder force is applied for stainless steel 409 Ni and Al-5182 aluminum. A number of experiments are carried out and analytical calculations are utilized to evaluate the results of simulations. In cylindrical cup drawing, simulation results of different constitutive models show good agreement with analytical calculations for thickness strain and effective stress distributions. In square cup drawing, simulation results of all the models displayed good agreement with the experimental results for edge contour comparisons, although the distributions of effective stress vary for different models within the cup. The numerically and experimentally obtained springback amounts are also in good agreement. The simulation results obtained for piecewise linear isotropic plasticity and power law isotropic plasticity models show better agreement with the analytical solutions and experiments.