多工序成形混合硬化模型及其在高强钢回弹补偿中的应用

摘要

Spring-back defect is considered to be a major problem in forming process of high strength steel,especially multi-stage forming,as the spring-back is more complicated due to an action of internal stress.The compensation method by adjusting tool shape geometry based on accurate spring-back prediction is the key to solve the problem.The combined hardening model for multi-stage forming is presented,and an iterated compensation method is applied with Ls-Dyna and Ls-Opt.In a self-designed experimental platform,the prediction model is shown to be more accurate in multi-axial tension and compression of DP600 comparing with other models.The compensation method is applied to the numerical simulation forthe multi-stage manufacturing process of an A-pillar,the experimental result demonstrates the feasibility and accuracy.%回弹缺陷是高强钢板料冲压时的一大难题,尤其对于多工序成形的零件,内应力作用引起的回弹问题更加复杂.在准确预测回弹的基础上修改模具型面的回弹补偿方案是解决这一问题的关键.为此,采用一种多工序混合硬化模型,结合有限元分析工具Ls-Dyna以及Ls-Opt,对模具型面迭代补偿.在自行改装的实验平台上,一项对高强钢DP600的循环拉伸压缩实验表明,与其他材料硬化模型相比,多工序混合硬化模型在多轴向的拉伸压缩实验中应力应变曲线的预测精度更高.某汽车A柱的多工序成形的回弹补偿结果证明该方法方便实用且精度高.