Shear band bifurcation and post-bifurcation analyses of FCC polycrystals under plane strain compression - ductile fracture of FCC crystals by shear band formation III

摘要

A numerical analysis, based on crystal plasticity, of the formation and the propagation of localized shear bands in FCC polycrystals is studied in order to establish the fundamental basis for predicting the forming limit of sheet metals. A deformation analysis is performed using the finite element polycrystal model. The critical state of shear band formation and the direction of the shear band of each element are predicted using the bifurcation theory. For the post-bifurcation analysis, a hypothetical 13th slip system is introduced into the element that satisfies the bifurcation condition. The results of the numerical analysis show that shear bands weaken the formation of deformation texture. Moreover, there are two different types of shear band formation. One is that shear bands propagate across grain boundaries, and the other is that they do not, which agrees qualitatively with the experimental results.