抄録
The theory of plasticity was first systematized in a textbook by R. Hill in 1950. This theory was further generalized in the framework of rational mechanics and is nowadays widely used in industrial as well as academic fields by means of the finite-element method. Because of the highly nonlinear process in metal forming, a finite-element simulation of metal forming processes suffers from various theoretical and technical problems. One of them is material modeling, i.e. a plastic constitutive model. Compared to the rapid progress in the analytical method of metal forming, a progress in the material modeling is not significant and a lot of problems still remain. Among them, a modeling of anisotropy is one of the problems of great importance. Recently a crystal plasticity model receives attention again as an alternative method to the conventional phenomenological constitutive model because this model can represent various phenomena including the anisotropy without giving specific assumptions. In this paper, progresses in the analytical method of metal forming and the material modeling during the period of the latter half of the twentieth century until now are comprehensively reviewed. Remaining problems to be solved and future perspectives are also discussed.
