Figure 1

Schematic illustration of the two types of shear band arrangements commonly observed in experiments.
(a) Semi-circular shear bands are found to connect the two notches, and these shear bands lead to out-of-plane surface steps8,9,10. (b) Shear bands emanating from the notch roots and leading to in-plane shear deformation11,12 (c) A three-dimensional illustration of the surface ledges/steps caused by these two types of shear bands.