【作者】 曹克利；

【导师】 邢忠文；

【作者基本信息】 哈尔滨工业大学 ， 机械制造及其自动化， 2008， 硕士

【摘要】 回弹是板料成形中的三种主要缺陷之一,也是其中最难控制的。回弹的存在直接影响到冲压件的形状、尺寸、精度和表面质量。特别是近年来高强度钢板在汽车车身制造中的大量应用,使得回弹问题尤为突出。高强度钢的机械性能和普通低碳钢有很大差异,钢板高强度化易引起塑性下降,成形性变差,而屈服强度的提高则引起面畸变和显著的回弹效应,增加形状不稳定性。因此,高强度钢冲压成形中的回弹是工业生产中的一个实际问题,也是学术界关注的热点。首先,在参考大量国内外技术资料的基础上,阐述了板料成形数值模拟理论中的关键技术。针对目前的研究现状,指出在分析板料成形问题时应采用大变形弹塑性有限元法,使用有限元模拟软件Dynaform,并结合弹塑性有限元方法对冲压件的回弹规律进行了研究。其次,分析了板料成形中产生回弹的原因,阐述了在回弹研究中所采用的建模方法和计算方法,同时分析了影响回弹预测的因素。然后,建立了曲面扁壳件的力学模型及有限元模型,分析了压边力、摩擦系数、板料厚度、拉深深度以及拉深筋对回弹的影响规律,介绍了回弹控制的一些方法,并利用模拟所得的结论和模具型面补偿方法对回弹进行了控制,研究结论对其它冲压件生产的回弹控制起到指导和参考意义。最后,通过正交实验方法分析各因素对回弹的影响程度,进而确定相关参数的合理数值,并通过实验加以验证。更多还原

【Abstract】 Springback is one of three main defects and also the most difficult to control. The existence of springback will affect the shape, size, precision and surface quality of the part. Springback problem becomes more impressing, especially with the wide use of the high strength sheet steel in the automobile body manufacturing. There are great differences between high strength steel and low carbon steel. High strength results in decreasing plasticity, poor formability, whereas improving yield strength will lead to surface aberration, obvious springback and unstable shape. So springback problem is both a problem that exists in the industry and a hotspot that the academia has paid attention to for a long time.Firstly, illustrates the key technology of the numerical simulation theory of blanks forming in details based on a great deal of overseas and domestic technical information.Secondly, it analyzes the reason of springback during the process of the blanks forming and introduces the way of constructing models and computation methods in the research of springback. It also analyzes the factors which affect springback forecast.Thirdly, the mechanics and finite element model of curvy flat hull part is founded and blank holder force, friction coefficient, the effect of thickness, and drawbeads on springback is analyzed. it introduces some ways to control the springback. And the simulation results and die surface compensation methods are used to control the springback. Then it obtains a good result in controlling the springback of other parts by using the research conclusion.Last but not the least, orthogonal experimental methods are used to study the impact of the various factors on springback, and then the reasonable value parameters are determined and verified by experiment.更多还原