Determining Localized Necking in Polycrystalline Sheet Metals Using the Bifurcation Phenomenon in Strain Evolution

The forming limit is an important failure criterion for polycrystalline sheet metals when approving the process. Recent developments in strain measurement technology, e.g., digital image correlation (DIC), enable evolution to be captured continuously and accurately. This new technology would improve measurements if onset of necking detection method was developed accordingly. paper proposes a based on bifurcation phenomenon detect localized through DIC measurements. inspired by physical understanding experimental observations phenomenon. eliminates derivative calculation from traditional method, while it can directly determine curves. robustness accuracy are also investigated experiments. Imperfection non-defect analyses, non-associated associated flow rules, were utilized compared determined results. provides satisfactory results used as alternative diagram (FLD).