Investigation of ductile rupture in U‐notched Al 6061‐T6 plates under mixed mode loading

Abstract The aim of the present research is to evaluate ductile failure of U‐notched components under mixed mode I/II loading conditions. For this purpose, first, several rectangular plates made of the aluminium alloy Al 6061‐T6 and weakened by central bean‐shaped slit with two U‐shaped ends are tested under mixed mode I/II loading conditions, and the load‐carrying capacity of the specimens are experimentally measured. Then, using the equivalent material concept, Al 6061‐T6, which is a highly ductile material, is equated with a virtual brittle material, and the load‐carrying capacity of the same U‐notched specimens virtually made of the equivalent material is theoretically predicted by using two well‐known stress‐based brittle fracture criteria. Finally, the theoretical failure loads of the virtual specimens are compared with the experimental ones of the real Al 6061‐T6 specimens. It is revealed that the experimental results could very well be predicted by means of both brittle fracture criteria without conducting time‐consuming elastic–plastic analyses.