应用逆向数值模拟分析覆盖件成形性能

研究了逆向数值模拟技术原理，针对覆盖件模型不规则而导致传统成形分析求解困难的问题，提出采用改进膜单元构造板料网格，以准确地描述毛坯变形行为；为提高边界条件定义的可信度，根据摩擦性质差异对非平面压料圈分类处理，凹凸模作用由冲压力和摩擦力的合力求解，开放式拉延筋则建立包含弯曲和摩擦效应的等效阻力模型；分析计算数据，并结合成形缺陷形成机理，完成产品成形性能评估．实验结果表明，经改进的算法能快速求解展开料参数、预测复杂产品破坏特征分布，适合用于覆盖件冲压设计。

Formability Analysis of Auto Panel Stamping Based on Inverse Numerical Simulation

Based on the inverse analysis principle, a novel numerical simulation approach has been developed to predict initial blank shapes and forming defects in complex-shaped auto panel stamping. Two new techniques are included in this approach. Firstly, to correctly describe blank deformation behavior, a kind of modified membrane finite element with bending effect is introduced. Secondly, with regard to the boundary condition definition, non-plane binders with variable blank holder force are classified and studied, the punch and die actions are replaced by a resultant force situated on the contact surface, and the work done by drawbead is evaluated at the nodes concerned according to an equivalent restraining force model, in taking into account the bending-unbending and friction. The rapid calculation method provides an easy process of part formability determination. The numerical results of example confirm its accuracy for design of auto panel stamping process.