共查询到19条相似文献,搜索用时 218 毫秒
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为了提高渐进成形过程中板料的成形极限和加工效率,提出了胀形-渐进成形的复合成形方法,通过胀形-渐进成形复合成形锥形件实验,研究了DC04钢板胀形-渐进成形复合成形锥形件和纯渐进成形锥形件的成形极限角和应变变化以及壁厚分布规律。结果表明:预成形高度为h=15 mm和h=25 mm时,复合成形零件的成形极限角分别为α极=66°和α极=69°;采用胀形-渐进成形复合成形锥形件,当胀形的最大减薄量发生在局部渐进成形区内,并且胀形和渐进成形的最大减薄量位置方向相反时,锥形件壁厚趋于均匀,提高了胀形-渐进成形的复合成形能力。 相似文献
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针对传统管件电磁胀形存在的壁厚减薄以及轴向变形不均匀的现象,提出了基于凸形集磁器的管件电磁胀形方法,通过调控径向电磁力分布以及轴向电磁力协同加载,为同时改善管件的壁厚减薄量过大和轴向变形不均匀提供了新的技术途径。为验证成形有效性,利用COMSOL软件构造了管件二维轴对称电磁-结构耦合模型,对比分析了有无凸形集磁器时径、轴向电磁力分布、轴向变形均匀性和壁厚减薄量变化,并研究了凸形集磁器内外壁高度对管件成形的影响。结果表明,相较于传统管件胀形,新成形方法下管件轴向变形均匀性提高了4.2倍,壁厚减薄量减小了33%。 相似文献
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电磁成形有限元模拟涉及多场耦合作用,其中结构场与电磁场之间的不同耦合方法对模拟结果影响显著。与松散耦合方法相比,顺序耦合方法考虑了板料变形对电磁场的影响,从而能够更精确的描述电磁成形过程。以ANSYS仿真软件为平台,建立板料电磁成形的顺序耦合三维有限元模型。通过不同耦合方法的模拟结果与实验结果对比表明,采用顺序耦合模型得到的板料变形与实验接近,而采用松散耦合模型得到的板料变形明显大于实验值。由此可见,顺序耦合模型是适合于电磁成形模拟的可靠模型。采用顺序耦合模型研究发现,放电电流的加载时间对板料电磁成形中板料变形的影响显著。当取放电时间为电流曲线的1.5个周期时,模拟结果与实验数据吻合最好。综合考虑计算效率与精度,板料电磁成形中放电电流的加载时间取1.5个周期为宜。 相似文献
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《塑性工程学报》2015,(6):71-77
针对大型铝合金曲面零件电磁渐进成形工艺中板料不均匀变形的问题,基于ANSYS多物理场模块建立电磁场-结构场耦合模型,对成形过程进行数值模拟分析,研究电磁成形线圈结构参数对板料变形行为的影响,包括:线圈层数、线圈匝间距、线圈层间距、导线截面积和导线截面形状。研究表明,线圈层数增加,板料变形均匀性降低,而板料的变形量增大,多层线圈有利于提高线圈的强度和使用寿命;线圈匝间距与导线的宽度越接近,板料均匀变形效果越好;矩形导线截面的线圈相对圆形导线截面的线圈使板料变形更加均匀;线圈层间距和导线截面积对板料均匀变形影响不大,但是合理的结构参数可以提高线圈强度。提出了一种非等间距线圈结构,非等间距线圈产生的电磁场和电磁力是不均匀的,在板料半径1/3处受到的成形驱动力较大,而这种不均匀的变形力,进一步改善了电磁成形中板料的变形不均匀性,电磁成形平板线圈能与变形后的板料较好的贴合,使大型铝合金曲面零件电磁渐进成形能通过多次放电连续均匀塑性变形。通过实验验证了线圈结构优化设计的可靠性,实验结果与模拟结果基本一致,误差在12%以内。 相似文献
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《锻压技术》2021,46(4):44-49
对于精度要求高、圆角半径小、厚度分布均匀的矩形截面管件,传统的成形工艺难以成形出合格零件。采用有限元模拟和实验研究的方法,研究了矩形截面小圆角管件胀-压复合成形工艺,分析了内压、上模压下量等关键参数对零件圆角半径和壁厚分布的影响。结果表明,增大内压和上模压下量有利于圆角的填充,采用适当的内压和上模压下量,矩形试件的相对圆角半径可以达到0.86。与常规的内高压成形中圆角及附近减薄严重不同,胀-压复合成形工艺的圆角及附近区域具有增厚的现象,有利于获得壁厚更加均匀的小圆角零件。在对成形规律进行研究的基础上,建立了矩形截面小圆角管件的成形工艺窗口,成形出了满足形状与尺寸要求的管件。 相似文献
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Electromagnetic incremental forming (EMIF): A novel aluminum alloy sheet and tube forming technology
《Journal of Materials Processing Technology》2014,214(2):409-427
Large parts cannot be shaped by conventional electromagnetic forming method due to the limitation of the strength of working coil and the capacity of capacitor bank. In this paper, based on the principle of single point incremental forming, a new method named electromagnetic incremental forming (EMIF) has been proposed. The method makes use of a small coil and small discharge energy to cause workpiece local deformation in a high speed. Finally, all local deformations accumulate into large parts. For the electromagnetic incremental sheet forming, the effect factors of processing parameters namely discharge voltage, vent hole, discharging times in a fixed position and the number of discharge region, on final sheet shape are investigated by using AA3003 aluminum alloy parts. In addition, two different simulation strategies are proposed to predict electromagnetic incremental sheet and tube forming process. For method 1: the technology like “birth–death element” is used to indirectly describe the movement of the coil and the morphing technology is used to make the air change with the workpiece deformation. For method 2: the coil can directly move to a special position and the remesh technology is used to consider the effect of the workpiece deformation and the movement of coil on magnetic analysis. It is found that method 1 cannot be used for electromagnetic incremental sheet forming process if overlap region exists in two adjacent discharge regions. However, method 1 can successfully predict electromagnetic incremental tube forming. And method 2 can be used for electromagnetic incremental sheet or tube forming. Both of the experimental and simulation results demonstrate that this new technology is feasible to produce large part. 相似文献
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建立了不同过渡区参数的TRB(Tailor-Rolled Blank)管液压胀形有限元模型,提出了一种离散不规则过渡区的新方法,研究了TRB管过渡曲线、过渡区长度和厚度差对胀形性能的影响规律。针对TRB管液压胀形,进行了正交设计,以数值模拟结果为基础,建立了BP神经网络预测模型,并将预测结果与数值模拟结果进行对比分析,验证了预测结果的精度。结果表明:各参数对胀形性能影响的区域不同,但都对最大成形高度影响显著,极差最大达6.47 mm,最小为2.88 mm;凹弧型过渡曲线的成形性能最差,最大的成形高度差为2.88 mm;增大过渡区长度有利于胀形,随厚度差增加,成形性能快速下降,其中厚侧成形高度差值达8.22 mm。单组预测值在误差范围内,预测模型能用于预测其他过渡区参数组合的TRB管胀形。 相似文献
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Huang Shangyu Chang Zhihua Wang Zhongren Wang Lifeng Yang Mei School of Materials Engineering Wuhan Automotive Polytechnic University Wuhan P. R. China School of Materials Science Engineering Harbin Institute of Technology 《中国有色金属学会会刊》1998,(3)
1INTRODUCTIONElectromagneticforming,esentialybeingakindofapplicationofimpulseintensivecurenttechniqueinmetalworking,dealswith... 相似文献
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Heon Young Kim Hee Taek Lim Hyung Jong Kim Dong Jae Lee 《Metals and Materials International》2007,13(2):87-92
The effects of 2D and 3D prebending on the forming limit in the tube hydroforming process of an automotive rear subframe are
evaluated and compared through finite element analyses and experimental tryouts. The influence of the strain path corresponding
to each prebending method is discussed in terms of a forming limit diagram (FLD) and a forming limit stress diagram (FLSD).
An incremental strain-to-stress transformation scheme to plot the FLSD from the FLD along an arbitrary strain path is proposed.
A tube hydroformability testing system designed and manufactured to provide an arbitrary combination of internal pressure
and axial feed is introduced. A forming limit diagram of the A6063 aluminum tube material is obtained from free bulging, T-shape
forming and cross-shape forming tests using this system. 相似文献
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Tendency of homogeneous radial deformation during electromagnetic compression of aluminium tube 总被引:1,自引:0,他引:1
Electromagnetic forming is one of the high-rate forming methods that can be extensively used to form and join axisymmetric metal sheet and tube. Tendency of homogeneous radial deformation during electromagnetic compression of aluminium tube was investigated through the design optimization method based on sequential coupling numerical simulation and experiments. The results show that the tendency depends on the length ratio of tube to coil (R), which has a critical value (Rc) corresponding to the relatively ... 相似文献
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电磁成形是一种高速率成形方法,它能够有效提高金属板材的成形极限。但是电磁成形过程复杂,涉及到磁场?结构场之间的耦合分析。数值模拟提供一种手段去解决耦合问题。然而,大多数的数值模拟都限于2D。建立3D有限元模型去分析电磁平板胀形。成形过程中考虑了板料与底模的接触和板料变形对磁场的影响。板料中心节点和半径20mm处节点的位移随着时间的变化与实验结果一致。分析了塑性应变能和塑性应变。 相似文献