Effect of plastic anisotropy on notch deformation behavior of 7075 high-strength aluminum alloy sheet subjected to axial tension

Abstract

The notch is an inevitable geometric characteristic in thin-walled structural components. However, the anisotropy in the notch deformation behavior of metal sheets has not been thoroughly investigated. To address this gap, we explored the effect of plastic anisotropy on the notch deformation behavior of the AA7075-T6 sheet subjected to axial tension at room temperature and quasi-static conditions. For this purpose, four types of notched tensile specimens are designed and tested along the rolling, diagonal, and transverse directions. The plastic anisotropy is examined by the dog-bone sample every 15° from the rolling to transverse directions. Full-scale numerical simulations for each notch tensile test were performed in ABAQUS/Standard based on the elastic–plastic constitutive framework with yielding depicted by the Yld2004-18p criterion. The results show that the established numerical models high fidelity reproduced the experimental measurements. It is found that the plastic anisotropy strongly affects the notch deformation of the sheet specimen subjected to axial tension, including strain concentration, plastic localization, stress state, and fracture initiation. Besides, the critical location of cracking in the material depends on the notch geometry parameter w/ρ, viz., the ratio of the half distance between roots of two notch (w) to the radius of the depth notch root (ρ). Another crucial contribution is to provide ideas for a researcher to control or design the path of strain localization by producing metals with specific textures to promote or delay fracture initiation. Accordingly, through the investigation of this work, we provide an essential reference for further engineering applications of high-strength aluminum alloy sheet products with notches.