Comparative wrinkle assessments for cup drawing of aluminum alloy sheets by analytical, experimental and numerical approaches

Abstract This study aims to introduce and validate the wrinkling limit curves (WLCs) obtained using various methodologies, including analytical calculations, experimental techniques combined with digital image correlation, and numerical simulations. These methods were compared and applied to the cup drawing part for accuracy assessment, using them as a framework for novel applications in the industrial sector. Firstly, Finite element (FE) simulations based on Hill’48 anisotropic yield criterion of Yoshida buckling samples were carried out for two aluminum thin sheet grades AA5052-O and AA5052-H32 with different heat-treating routes under both rolling and transverse directions. Hereby, WLCs of both aluminum sheets were determined, and their formability regarding non-flange wrinkling was novelly characterized and newly evaluated.Subsequently, the applicability of developed WLCs was evaluated through experimental and FE analysis of conical cup drawing tests, in which varying blank holder forces were incorporated to induce severe and non-flange wrinkling occurrences. The results showed that the AA5052-O sheet exhibited higher formability and a greater tendency for wrinkles than the AA5052-H32 sheet attributed to variations in their anisotropic and strain hardening behaviors. Moreover, the WLCs by FE simulations provided the most accurate predictions of the onset of non-flange wrinkles, whereas the analytical method obviously tended to overestimate experimental results. The WLCs for the transverse direction indicated higher forming limits than those for the rolling direction, correlating well with the material's anisotropy.