板料冲压成形回弹有限元数值模拟研究.pdf

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锻压技术 2004 年第 4 期
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板料冲压成形回弹的有限元数值模拟研究
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刘艳芳施法中
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(北京航空航天大学机械工程及自动化学院)
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摘要: 随着对冲压件的尺寸精度要求的不断提高1 1 1 , 精确预测给定冲压件的回弹量大小及分布显2 2
得非常重要。采用无模法模拟卸载回弹过程时1 1 , 需要以加载成形后的应力为基础。本文给出了加载
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成形中的应力计算方法, 并采用无模法建立了卸载回弹的计算模型。文中提出一种不同于传统的初
始单元弹性化处理的方法, 提高了回弹的计算精度。研究了卸载因子的取值规律对回弹计算的影
响。利用自行开发的软件 Sheet Form 模拟分析 NUM ISHEET’93 标准考题中 U 型件深冲压的回弹
情况, 验证了该方法的有效性。
关键词: 板料冲压成形弹塑性有限元数值模拟回弹
Study on f inte element numerical simulation of springback in sheet metal stamping forming
LIU Yan fang SHI Fa zhong
(School of Mechanical Engineering & Automation , BeiHang University)
Abstract : Accurate prediction of springback is ing more important in automotive sheet stamping operations while
requirements for high accuracy in formed products has been increasing. Simulation of the unloading process is based on the
stress state at the end of the loading process analysis. The stress calculation in the loading process and the springback model
with tools removed and all contact nodal forces recovered were investigated. A distinct method from the traditional one deal
ing with the initiation of sheet elements waspresented , which is proved to improve the accuracy of the springback prediction.
The influence of the unloading factor on springback with the assumption of proportional loading path for stress relaxation was
also discussed. Spring