板料成形中悬空区起皱过程的数值模拟

Numerical Simulation on Wrinkling of Noncontact Region in Sheet Metal Forming

以逐级更新Lagrange描述的有限变形虚功原理为理论基础．采用Mindlih退化板壳单元，开发板料冲压成形起皱过程的有限元数位模似，软件WRSIM，模拟了3种典型悬空区起皱问题．所得结果与实验观察基才一致。该软件可与其他成形过程数值模拟软件一起用于模具CAE，以便在校具设计阶段分析冲压件的可成形性。

The onset and growth of wrinkling or puckering in the noncontact region of a sheet forming part is investigated numerically. The FE code for wrinkling simulation in sheet metal forming is developed. It employs eight node Mindlin degenerated shell element and up dated Lagrange formulation. Three typical wrin kling processes due to nonuniform tension stress, shear stress and direct compressive stress are simulated with the code. The results are in agreement with experiments. The code can be used in the dies CAE together with other process simulation software so that the geometric defects and stability of parts can be analyzed in design ing dies.