Basic Formulation of Implicit-Type Elastic-Plastic FEM for Void Material and Application to Cutting Simulation.

This paper presents the implicit formulation of elastic-plastic constitutive equation for Gurson's yield function which includes the effect of microvoid and can treat ductile fracture. In this formulation, radial return method, which is normally used for Mises's yield function, is applied to Gurson's one. This stress calculation algorithm is applied to the deformation analysis based on implicit-type elastic-plastic FEM. As an example of application, uniaxial deformation process is analyzed by this method. The chip formation process in orthogonal cutting is simulated by treating the ductile fracture of tool edge without renumbering the nodes. The distribution of void fraction in chip is calculated. The simulated result indicates this method is useful for an analysis of large deformation process including ductile fracture such as metal cutting.