改进的一步模拟法及其在板料成形分析中的应用

研究了基于形变理论的板料成形一步模拟法（又称为反算法）．采用由CST（Constant Strain Triangular）薄膜单元和DKT6（Discrete Kirchhoff Triangular）板单元组合而成的DKTl2壳单元，既可以考虑面内薄膜力的作用，也可以叠加弯曲效应对单元的影响．引入Barlat提出的6个应变率分量表示的塑性势函数，可以更好地描述板料面内各向异性．用弧长展开法获得初始解，并利用反向变形法对其进行改进，增强了求解的稳定性，提高了计算精度．盒形件的拉深实例证明，该改进的方法可以更为有效地模拟实际变形情况，分析结果具有较高的可信度．

The Improved One Step FEM and Its Application in Sheet Metal Forming Analysis

The theory and method of one step FEM(also called inverse approach) of sheet metal forming based on deformation theory of plasticity were explored.In order to take into account the bending effects,this approach with CST(Constant Strain Triangular) membrane element and DKT6(Discrete Kirchhoff Triangular) plate bending element superposed to obtain the DKT12 shell element was fully introduced.Strain-rate potentials expressed in six-dimensional space proposed by Barlat was adopted to prescribe the plane anisotropic of sheet metal.A reverse deformation method was implemented to improve the initial solution obtained by radial length developing method.An application to a square box drawing was presented with emphasis on the efficiency and usefulness of the proposed improved method.