中国机械工程

• 先进材料加工工程 • 上一篇    下一篇

考虑变形热和摩擦热效应的热力耦合冲压研究

聂昕1;肖兵兵1;申丹凤2;郭文峰1   

  1. 1.湖南大学汽车车身先进设计制造国家重点试验室,长沙, 410082
    2.湖南湖大艾盛汽车技术开发有限公司,长沙, 410082
  • 出版日期:2020-08-25 发布日期:2020-09-17
  • 基金资助:
    湖南省自然科学基金资助项目(2020JJ4196);
    柳州市科技计划重大专项(柳科攻2018AA20503);
    宝钢股份科技合作项目(201891930854);
    长株潭标志性工程计划资助项目(2019XK2104)

Research on Thermal-mechanical Stamping Forming Considering Deformation Heat and Friction Heat Effects

NIE Xin1;XIAO Bingbing1;SHEN Danfeng2;GUO Wenfeng1   

  1. 1.State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,Hunan University,Changsha,410082
    2.Hunan Huda Aisn Automotive Technology Development Co.,Ltd.,Changsha,410082
  • Online:2020-08-25 Published:2020-09-17

摘要: 以DP780材料为研究对象,在20~140 ℃温度区间、0.001~0.1 s-1应变速率区间内进行恒温拉伸试验,分析了真实应力-应变变化趋势,建立了基于Norton-Hoff模型的材料本构方程,该本构方程能够较好地表征DP780在冷成形过程中与温度相关的塑性本构关系。结合Norton-Hoff本构模型,以及与温度、压力相关的摩擦模型,采用理论研究与数值模拟结合的方式,研究DP780钢板变形热和摩擦热的自发热产生机理和宏观特征。根据完全热力耦合数值模拟理论,考虑将温度场和应力场、应变场等进行耦合分析,提出一种考虑变形热和摩擦热效应的冲压成形研究方法。通过U形件冲压试制试验,得到DP780钢板冷成形条件下的试验回弹结果。对比传统冷冲压模拟结果和考虑自发热效应研究方法下的模拟结果发现,考虑自发热效应的冲压成形模型在模拟侧壁时准确性提高了10.1%,在模拟法兰时准确性提高了23.2%。

关键词: 高强钢, 冲压, Norton-Hoff本构模型, 变形热, 摩擦热, 热力耦合

Abstract: The DP780 material was subjected to constant temperature tensile test in the temperature range of 20~140 ℃ and the strain rate range of 0.001~0.1s-1, and the true stress and strain change trends were analyzed. The constitutive equations of materials were established based on the Norton-Hoff model, which might better reflect the shaping constitutive relationship of DP780 during different cold forming processes. Combined with the Norton-Hoff constitutive model and friction model related to temperature and pressure,the combination of theoretical research and numerical simulation was used to study the mechanism and macroscopic characteristics of deformation heating and friction heating of DP780 steel plates. According to the theory of complete thermal coupling numerical simulation, considering the coupling analysis of temperature field, stress field and strain field, a research method of stamping was proposed considering deformation heat and friction heat effects. Through the stamping experiments, the forming results and springback characterization of DP780 steel plates applied to U-shaped parts were obtained. Comparing the simulation results of the traditional cold stamping and the new analytical method considering self-heating effects, it is found that the new stamping forming research method improves the accuracy by 10.1% on the sidewall and the accuracy by 23.2% at the flange.

Key words: high-strength steel, stamping, Norton-Hoff constitutive model, deformation heat, friction heat, thermal-mechanical coupling

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