金属板料冲压成形的数值模拟

本文采用有限元动力显式算法模拟金属板料冲压成形的加工过程。四结点蜕化壳单元和刚体壳单元分别用来建立权和模具的有限元模型；更新Ｌａｇｒａｎｇｅ法和速率型本构关系被用来处理板料变形中的大应变和大转动；材料模型采用塑性各向异性屈服与等向强化模型；通过主从面模型定义板料和模具的接触，接触算法采用运动约束法，摩擦力用库仓定律计算；并利用动力松弛法对回弹过程进行了计算。模拟结果和实际零件比较，证明模型合理，算法稳定，结果可靠，具有良好的应用价值。

Computer Simulation of Deep Drawing Process in Sheet Metal Forming

Dynamic explicit FEM code is employed to simulate the process of deep drawing in sheet metal forming. Four-node degenerated shell element and rigid shell element are used in our FEM model. Updated Lagrange formu- lation and rate form constitutive equation are adopted to solve the problem of large strain and large rotation in sheet forming process. Sheet metal material property is described by plastic anisotropy yielding model and isotropic hardening model. Master surface-slave surface contact model is used to define the contact between tools and blank. Contact constraints are enforced with a kinematic algorithm and friction stress is computed by Coulomb friction law. Dynamic relax- ation method is used to treat springback after forming stroke. The numerical results are in good agreements with those obtained by practical product experiment. The method and algorithm are proved robust and reliable.