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成形极限图是判断板料成形中是否会发生失效的重要依据。渐进成形中的板料成形极限图和传统冲压成形极限图有显著不同。板料传统冲压成形极限图测试方法已较为完善,而对于渐进成形尚没有形成统一的标准。本文在已有的测试方法基础上,提出了通过渐进成形圆弧沟槽、十字交叉圆弧沟槽直至板料端部破裂后,测量破裂位置最大和最小主应变以获得板料渐进成形极限图的新方法。通过数值模拟研究,分析了采用该方法对板料进行渐进成形时板料局部的应变状态,表明该方法可行;并使用该方法得了0.9mm厚工业纯铝1060板料的渐进成形极限图。 相似文献
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板料渐进成形技术作为柔性制造技术,其研究已经取得相当进展。但是在进给轨迹连续的普通渐进成形中,材料在成形过程容易产生沿轨迹方向的推挤,而产生不必要的变形,影响加工能力和加工质量。通过圆弧沟槽实验,对比点压渐进成形和连续渐进成形,发现点压渐进成形可获得的沟槽长度为60.5 mm,大于连续渐进成形中48.9 mm的沟槽长度;破裂位置最大主应变分别为1.212和0.982,说明板料点压渐进成形时的成形性能比连续渐进成形好。通过改变点压渐进成形中正弦波的波长和振幅,说明两参数对成形性能的影响。采用成形性能更好的点压渐进成形,可减少多道次渐进成形的成形道次,拓展渐进成形所能成形的零件结构类型。 相似文献
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通过胀形试验和以沟槽法为基础获取普通板料渐进成形极限图的方法,分别获取TRIP590板料的传统成形极限图和渐进成形极限图。为了直观地比较TRIP590板料在不同成形方式中具有的成形性能以及验证获取的渐进成形极限图是否满足于TRIP590板料成形,设置了变角度圆锥台和变角度方盒进行验证。两组试验证明:TRIP590板料在渐进成形中的成形性能远强于传统成形,并且获取的线性方程为ε2=0.525 4ε1+0.989 1的渐进成形极限图也适用于TRIP590板料的成形。 相似文献
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曲面翻边是板料成形工艺中一种重要的成形方法,但在实际生产中,曲面翻边极易产生破裂、回弹、起皱等缺陷,严重影响产品的美观性和精确度.为了预测和控制此缺陷,对曲面翻边的3种成形工艺进行了分析,并给出了3种成形工艺中,翻边高度、直边长度和底面圆弧半径3个参数的不同数值所对应的应变图及应变曲线图.利用这些结果对3种成形工艺进行了比较,从而为零件的设计和实际生产提供参考,以避免加工的零件产生缺陷. 相似文献
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基于塑性理论建立了比例加载条件下双向拉伸应力应变关系,结合Swift分散性失稳准则,提出了一种建立板料成形极限应力图的方法。分别应用Hill 48和Hosford屈服准则以及单向拉伸性能参数,建立了铝合金板(r<1)和薄钢板(r>1)两种材料的成形极限应力图(FLSD),分析表明,不同的屈服准则的选取对于成形极限应力曲线有不同的影响,对于不同类型的材料屈服准则的影响程度也不同。与由通常的成形极限图(FLD)转换所得到的成形极限应力图(FLSD)进行了对比分析,结果表明,所提出的方法计算过程更为简便,并能较为准确地建立成形极限应力图,可以作为复杂加载路径下的成形极限破裂判据。 相似文献
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New experimental data is presented on Forming Limits in Single Point Incremental Forming (SPIF), which is a sheet metal forming process which does not require dies. A Box-Behnken Design of Experiment is used to develop the experimental plan and analyze data. In former work, the most critical factors affecting Single Point Incremental Forming were found to be material type, material thickness, formed shape, tool size, and incremental step size. In this experimental work, new results are presented as graphical response surfaces which show the forming limit for all the critical factors listed previously. In addition, forming limits are presented in terms of Forming Limit Diagrams. 相似文献
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Yingbing Luo Craig Miller George Luckey Peter Friedman Yinghong Peng 《Journal of Materials Engineering and Performance》2007,16(3):274-283
In this paper, the superplastic forming (SPF) potential of two fine-grained 5083 aluminum alloys were studied under various
stress states with the use of both high temperature tensile testing and pneumatic bulge testing. Experiments with the pneumatic
bulge test were performed at temperatures ranging from 475 to 525 °C under three different strain paths ranging from equi-biaxial
to approaching plane strain. The effects of temperature on total elongation, m-value, final thickness distribution, dome height, and cavitation were investigated for the case of uniaxial and equi-biaxial
stretching. Increased temperature in bulge forming was found to improve the thickness distribution in the formed parts, but
did not have a significant effect on dome height. The shape of the forming limit diagram (FLD) was found to be significantly
different than that of FLDs commonly used in room temperature stamping. Results indicate that determination of forming limits
in SPF cannot be represented with a simple FLD and additional metrics such as external thinning and internal cavitation need
to be considered to determine a material’s SPF potential.
This article was presented at Materials Science & Technology 2006, Innovations in Metal Forming symposium held in Cincinnati,
OH, October 15-19, 2006. 相似文献
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Incremental Sheet Forming (ISF) is a process capable of producing complex sheet components by the CNC movement of a simple tool in combination with simplified dies. Earlier work revealed two major process limits, namely the limitation on the maximum achievable wall angle, and the occurrence of geometric deviations. The work detailed in this paper focuses on forming strategies to overcome these process limits, including the processing of tailor rolled blanks. Additionally, finite element modelling of the process is presented and discussed with respect to the prediction of the forming limits of ISF. 相似文献
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R. Kopp 《CIRP Annals》2002,51(1):195-198
The exceptionally flexible forming technology shot peen forming is used primarily on large, three-dimensionally curved sheet metal in the aircraft and aerospace industries. Depending on the kinetic shot energy, both convex and concave curvatures will be generated. The most recent development, double-sided simultaneous shot peen forming, brings about a higher productivity of the entire process. FEM simulations of single and multiple impacts are presented in order to evaluate the characteristics of concave curvatures generated by both single and double-sided peen forming. 相似文献
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电磁成形技术在粉末成形中的应用 总被引:1,自引:0,他引:1
介绍了电磁成形技术、粉末挤压成形方法以及电磁成形技术在粉末成形中的应用.用电磁成形技术压制粉末材料是获得高密度、高性能粉末冶金制品的一种有效方法,是低成本制造高密度陶瓷零件的新途径. 相似文献
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A novel class of ‘paddle forming’ processes for forming pronounced features within sheet metal components is presented. The processes are incremental in nature and are characterised by having contact between the tool and the workpiece along a short line segment. The processes lead to high through-thickness shear strains, which have been shown to increase the possible deformation before ductile instability occurs. Paddle forming tools, which are cheap and simple to manufacture, can be applied to the faces or edges of sheets, tubes and disks. Four example processes are demonstrated, each showing high deformation and pronounced through-thickness shear strain. 相似文献
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利用有限元分析通用软件MSC.Marc对变截面U型材辊弯成型进行仿真模拟分析。本文对变截面辊弯成型仿真采用轧辊轴向加工技术(代替法向加工技术),对角度连续变化的变截面U型材分别进行立辊加工和平辊加工成型模拟分析。得出结论揭示了平辊加工和立辊加工对变截面型材在90°折弯变形时产生的影响,对实际生产具有一定的指导意义和参考价值。 相似文献