Material damage and forming limits of textured sheet metals

In this paper, the evolution of preferred grain orientation and its effect on plastic deformation and mechanical properties are discussed based on crystallographic theory and the continuum mechanics of textured polycrystals (CMTP) technique. Mechanical damage due to microdefect development is also studied using continuum damage mechanics (CDM). The forming limit strains in biaxially-stretched textured sheet are predicted using the Marciniak-Kuczynski (M-K) model with modification to take into account the damage due to both texture evolution and the presence of microdefects. The results show that the proposed method can significantly reduce the conventional over-estimation of limit strains in the biaxial stretching state.