A numerical analysis of the crack-tip plastic zone in glassy polymers

This paper reports on a finite element analysis of the crack-tip plastic zone in viscoplastic glassy amorphous polymers. The constitutive model employed in this study accounts for the typical shear yielding behaviour of glassy polymers, i.e., the intrinsic softening upon yielding and the subsequent orientational strain hardening. The modified boundary layer approach is adopted to model the local finite-strain deformation processes around the crack. Numerical results show that the shape of the mode I plastic zone in glassy polymers depends greatly on the softening property of the material, and is quite different from that described by the Von Mises criterion for yielding in metals.