中文摘要：

传统的板料成形反向模拟法（Traditional inverse analysis method,TIAM）没有考虑变形历史对成形过程的影响,使得反向模拟法计算的应力值与实际情况有较大偏差。金属在流经凹模圆角时受到强烈的弯曲—反弯曲作用,并且凹模圆角处往往是应力集中的区域,能否较为准确地描述该区域变形历史,关系到反向模拟法应力/应变计算精度。针对反向模拟法无法准确预测成形零件应力分布的缺点,提出一种快速搜索流经凹模圆角区域单元的方法,对该部分单元进行应力修正。采用一种高效的多步加载应力应变本构关系模型,避免了增量有限元法应力应变更新算法的复杂性,同时充分考虑了凹模圆角对金属变形历史的影响。NUMISHEET’93U形件弯曲的标准考题中,通过与增量有限元分析软件ABAQUS/Standard计算结果的比较,验证了采用所提出的多步加载本构关系模型可以有效地反映变形历史的影响,获得更为接近真实情况的应力分布。

英文摘要：

The traditional inverse analysis method （T1AM） of sheet metal stamping gives bad estimation of stress distribution mainly due to the loss of history of deformation. Elements near the die entrance radius are subjected to bending and unbending during forming operation. Moreover, stress accumulation can usually be found in die entrance zone. A fast and reliable searching scheme is used to find elements passing by die entrance radius during the deformation process. The followed procedure has been used to modify stress distributions. An efficient stress-strain relation for multi-step loading is introduced to update stress distributions. This constitutive equations can avoid the complexity of incremental finite element method （FEM） based stress/strain updating algorithms, while can consider the effects of die entrance radius on deformation history. Deep drawing of the U-bending test proposed in Numisheet＇93 demonstrates that these constitutive equations can significantly enhance the prediction of stress distribution by comparison with incremental FEM based software ABAQUS/Standard.