抄録
Deformation analysis of shearing process is carried out by using finite element method (FEM). Gurson-Tvergaard-Needlman (GTN) model is applied as a fracture criterion because ductile fracture behavior is a dominant factor in shearing process. Ductile fracture involves micro void nucleation, growth and coalescence of voids. To predict void nucleation in FEM analysis, a void nucleation critical strain model is proposed. Furthermore a notched round bar tension test using image analysis is proposed for deciding material properties relating ductile fracture. Gradual changes in the necking shape and tensile load are measured by using the test. From the results, strain and stress history at the necking section of tensile specimen and relationship between stress triaxiality and microvoid nucleation are obtained. Additionally, obtained damage parameters are introduced to the deformation analysis of shearing process and the results are compared with the experimental result.
