Effects of pre-notches on the self-organization behaviors of shear bands in aluminum alloy

The effects of pre-notches with different radii of curvature on the self-organization of multiple adiabatic shear bands (ASBs) in the 7075 aluminum alloy were investigated by means of the thick-walled cylinder (TWC) technique and finite element method (FEM) for the first time. Most of the shear bands nucleate at the notch tips, and distribute in the clockwise (or anticlockwise) direction. The number of shear bands initiated in the notched specimen is much less than that in the un-notched specimen. The simulation results are in good agreement with the experimental results. The stress concentration is noticeable at the notch tip. Shear bands nucleate firstly at the notch tips under perturbation in the strain/stress fields, which produce a greater shielding effect on the large area in the vicinity of the notch. Sharper notches experience higher levels of local effective strains, whose values are about one order of magnitude higher than the global effective strains. The sharper the notches, the stronger the shielding effect in the self-organization of multiple shear bands.