Inelastic deformation and localization in polycarbonate under tension

It is demonstrated that uniaxial tension deformation in polycarbonate and other polymers that exhibit large inelastic deformation is unstable beyond a certain stretch[ The instability _rst appears as a shear banding phenomenon at a characteristic angle and is then followed by a stabilized neck generation and propagation[ The intrinsic material law for polycarbonate is used in a numerical implementation to reproduce completely the deformation behavior observed in uniaxial tension[ In particular\ it is demonstrated through numerical simulations\ that intrinsic material softening is not necessary for the formation of a shear band and continued growth of a stable neck and further that the interpretation of the tensile response in terms of the constitutive behavior of the material poses signi_cant problems[ 0887 Elsevier Science Ltd[ All rights reserved[