为了解决传统静力隐式增量算法收敛困难的问题，提出一种基于大步长静力隐式有限元算法的板料成形快速模拟算法，即将板料成形中的弯曲和拉伸变形过程分开计算，根据板料和模具的位置关系计算中间构形.同时，提出了一种基于预应力膜单元的中间构形的准确构造方法，其中采用接触判断算法确定板料与模具的接触状态，接触区的板料形状取决于模具形状，而非接触区的板料形状采用预应力膜单元的平衡迭代计算获得，并采用平衡迭代方法计算中间构形，通过实际算例验证其有效性.结果表明，所提出的算法能够快速计算理想的中间构形，符合快速模拟的计算要求.
The large time step static implicit finite element method (FEM) for sheet metal forming simulation is presented to alleviate the convergence problem of the traditional implicit incremental FEM, and the simulation process of sheet metal forming is divided into bending deformation and tensile deformation. According to constraints of positions between the blank and mold, the shape of bending deformation which is called intermediate configuration is calculated. Meanwhile, a method based on pre-stress membrane element for constructing an intermediate configuration is also proposed in this paper. In this method, the contact states of the blank nodes are determined by the contact algorithm. The contact zone of blank is determined by the shape of mold, the non-contact zone is calculated with iterations for equilibrium equations by the pre-stress membrane element. The result shows that the proposed algorithm could obtain the appropriate intermediate configurations quickly and provide precise surface sliding constraint for tensile deformation.
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