板料成形有限元模拟中的拉格朗日分析方法

数值模拟中的模拟方法对于建立一个可信赖的有限元模型非常重要。板料成形中包含大变形、大位移和摩 擦行为,模拟结果对不同的有限元模型有很大的不确定性。采用有限元软件MARC基于不同拉格朗日法建立了一 个有限元模型来分析深冲压成形过程。模拟中板料作为变形体,模具看作刚体,接触面间的摩擦约束采用修正的库 仑摩擦模型。板料应变、厚度的模拟和实验结果比较表明完全拉格朗日法(T.L.)和更新拉格朗日法(U.L.)的主 要区别在大变形和大位移上,小变形和小位移两者吻合较好。

Lagrangian Methods of FEM Simulations in Sheet Metal Forming Process

Simulation method has become an increasingly important problem to establish the trustworthiness of models in the FEM simulations. Finite element(FE) models in sheet metal forming, which involves large deformations, large displacement and friction, are uncertain for different methods. Finite element models based on different Lagrangian methods have been used to analyze the deep drawing process by the FE software, MARC. The tools are modeled as rigid surfaces. The blank is modeled as a deformable body. The interaction of sliding surfaces is modeled with a modified Coulomb friction law. The FE results of strain and thickness distributions are validated by comparison with the experiment. It is shown that the main difference of Total Lagrangian (T.L.) formulation and Updated Lagrangian (U.L.) formulation lies in the large displacement and deformation, while they agree well for small displacement and deformation.