Localized shear zones growth

Figure 11. Growth of a localized shear zone in rubber-toughened epoxy, obtained using the spherical model. The yielded elements at the different steps are shaded. The applied strain (loading direction) is 3.0% (top), 4.0% (middle), and 5.0% (bottom).

PC shows either craze or shear behavior, with no mixed behavior, i.e., successively regenerated localized DCG zones. There is a sharp transition between the craze and the shear branches, as seen in Fig. 35. The competition between crazing and shear is temperature and stress sensitive. The mode, once determined, persists as the barrier is high between these two modes. At 75 °C and above, no craze-crack growth is observed, although shear fracture does persist down to —25 °C, albeit only at high stresses. 

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