Effect of Anisotropy and Inertia on Shear Banding: Instability of BiaxialStretching. (Reannouncement with New Availability Information)

摘要

The instability of biaxial stretching leading to the development of shear bandsin viscoplastic materials with both isotropic and kinematic hardening is examined. We evaluate the effect of anisotropy and inertia on the onset of instability and examine the development and evolution of an inhomogeneous deformation structure using both a linear and a nonlinear finite element analysis. We show that the back stress and plastic spin, modeling deformation induced anisotropy and texture development have influence on the critical state at which the first instability occurs. The corotational rate of the back stress and its relation to the spin of the substructure produces apparent softening, causing instability at positive strain hardening. When decreasing the magnitude of the spin of the substructure by varying the plastic spin parameter the critical value of the hardening parameter decrease towards zero. We also show that at the onset of instability, the linear analysis predicts the development of a periodic structure of square cells implying that it is far from being localized. The nonlinear finite element analysis also predicts the formation of a square cell pattern at the onset of instability which evolves into localized shear bands far into the post localization regime. shear banding.