Modeling of constitutive behavior and ductile fracture of AA5A06 aluminum alloy sheet in warm hydroforming process

Abstract

In order to predict the formability of lightweight materials, the flow stress and fracture behavior of AA5A06 aluminum alloy which is very sensitive to temperature and strain-rate were investigated in this study. First, a modified Misiolek constitutive equation with a work-soften term is proposed to calculate the flow stress of the sheet metal. To predict ductile fracture in sheet forming operations, Cockcroft-Latham damage criterion is applied here and ductile fracture threshold under each condition is estimated using Response Surface Method. Finally, warm hydroforming deep drawing tests were conducted at various conditions and the experiment results are compared with the numerical simulation result to evaluate the new model’s feasibility and accuracy in forecasting the mechanical response of the material in warm forming conditions. Results show that the proposed model has a good accuracy compared with the traditional power law models and the FEM simulation conforms well to the tests.