Failure Evaluation of Aluminum Alloy in Two-Step Hybrid Forming Process at Elevated Temperature

Abstract

In the thesis, the equivalence between the localization criteria and the fracture criteria was confirmed by an attempt to predict the failure phenomenon induced by abrupt strain localization in the two-step hybrid forming process of aluminum alloys at elevated temperature. As the localization criteria, an extensive and systematic method without a fracture criterion was utilized to foresee the initiation of failure. As the fracture criteria, a deformation path and effective strain-rate sensitive fracture model was newly introduced. It was proven that sophisticated material characterization is crucial to predict failure without a fracture criterion and the localization criteria and the fracture criteria are identical as a forming limit in case of failure with abrupt strain localization.