강소성 유한요소법을 이용한 자동차 판넬 성형공정의 평면 변형해석

Abstract

A plane-strain finite element analysis of sheet metal forming is carried out by using the rigid-plastic FEM based on the membrane theory. The sheet material is assumed to possess normal anisotropy and to obey Hills new yield criterion and its associated flow rule. A formulation of initial guess generation for the displacement field is derived by using the nonlinear elastic FEM. A method of contact treatment is proposed in which the skew boundary condition for arbitrarily shaped tools is successively used during iteration. In order to verify the validity of the developed method, plane-strain drawing with tools in analytic expression and with arbitrarily shaped tools is analyzed and compared with the published results. The comparison shows that the present method can be effectively used in the analysis of plane-strain sheet metal forming and thus provides the basis of approximate sectional analysis of panel-like sheet forming.