FEM Design of Cruciform Biaxial Tensile SpecimenBased on Limit Strain Analysis

A cruciform biaxial tensile specimen with chamfer in arm and center region is designed by the method of finite element numerical simulation in order to realize the complex loading using cruciform biaxial tensile test and study the limit strains of sheet metals under the complex strain loading paths. Finite element calculated model is established. An optimum shape of specimen is obtained on the basis of the following conditions: the stress distribution in the center region is uniform and large deformation is obtained easily during stretching of the specimen. Different strain paths in the center region can be realized by adjusting the velocity boundary conditions. This paper provides the basis for the study of sheet forming limit under the complex strain loading paths.