PLASTIC LOCALIZATION IN ANISOTROPICALLY HARDENING DAMAGED MATERIALS

The necessary conditions for the initiation of plastic localization ba nds are obtained. The material considered is rigid-plastic, strain rat e sensitive, anisotropically hardening and thermally softening. Inside the bands of localized plastic deformation the strains are much highe r than in the rest of the material. This leads to material damage. The development of microcracks and voids makes the material more deformab le, which then has an influence on the initiation of localization band s, due to the softening effect. The development of the damage is descr ibed by means of a scalar variable, according to the model, proposed b y Lemaitre. The influence of the different factors - plastic strain, t emperature and damage on plastic localization is studied. It is shown that plastic localization can occur even in the isothermal case, due t o the structural changes in the material.