共查询到18条相似文献,搜索用时 156 毫秒
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基于数值模拟的拉延筋约束阻力计算方法研究 总被引:1,自引:0,他引:1
在汽车覆盖件拉深成形中,拉延筋可以在较大范围内调节和控制板料的变形程度和变形分布,抑制多种成形质量问题的产生.其中,拉延筋几何参数起着重要的作用.本文以矩形拉延筋为例,建立了拉延筋约束阻力计算有限元模型,对拉延筋几何参数与约束阻力之间的关系进行分析研究.结果表明:拉延筋约束阻力与凹槽圆角半径和凸筋圆角半径成反比,与筋高成正比.结合某轿车B柱加强板实例,通过优化其拉延筋结构参数,得到当1号等效拉延筋高8mm、凸筋和凹槽圆弧半径3mm;2号等效拉延筋高4 mm、凸筋和凹槽圆弧半径6mm时,该制件成形质量达到最佳. 相似文献
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板料冲压成形数值模拟中等效拉延筋模型的建立与实现 总被引:9,自引:0,他引:9
设置拉延筋是板料拉深成形过程中控制材料流动的有效方法。在板料成形数值模拟中,为节省计算时间,常采用等效拉延筋模型。本文在参考国内外有关资料的基础上,建立了一种等效拉延筋模型。模型中考虑了拉延筋约束力、塑性厚向应变以及垂直于压料面的约束保持力的影响,并在程序中予以实现。文中给出了一个计算实例。 相似文献
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对拉深成形过程中板料经过梯形拉深筋时的变形情况进行了分析,运用能量法建立了一种简单实用的梯形拉深筋等效约束阻力计算模型,利用Dynaform软件对梯形拉深筋的等效约束阻力进行了模拟,将计算结果与模拟结果进行了比较。分析结果表明:在拉深成形过程中,如拉深筋设置在圆弧部位,板料经过拉深筋后最终等效约束阻力是随拉深过程的进行而变化的;板料通过设在直线段的筋产生的等效约束阻力,在一定的压边力下,其值为恒定的值;理论计算与模拟值基本吻合,在数值模拟时,该模型可以作为等效拉深筋使用。 相似文献
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传统的冲压模具设计中,拉延筋设计和布置主要依靠经验,这使得模具设计和制造周期延长.以某汽车侧壁外板的拉深工序为例,讨论了神经网络技术与遗传算法在拉延筋优化设计中的综合应用问题.建立了反映板料成形参数与拉延筋阻力之间非线性映射关系的BP网络模型.利用该训练好的神经网络可以实现拉延筋的优化设计.由于相对于进行工艺试验来说数值仿真比较省时省力,因此,利用Dynaform模拟汽车侧壁外板的拉深成形过程,建立训练样本.在网络的训练方法上利用遗传算法进行了优化,有效地提高了神经网络的模拟精度. 相似文献
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基于数值模拟的C柱内板拉延筋设计与优化 总被引:2,自引:0,他引:2
合理布置拉延筋是控制汽车覆盖件拉延成形质量的重要手段。根据C柱内板的结构设计拉延数模,基于Dynaform软件平台对不同拉延筋布置形式下该零件的拉延成形过程进行数值模拟,通过对比分析模拟结果,确定了拉延筋的合理布局。在此基础上,结合正交试验法对压边力、拉延筋高度和拉延筋圆角半径进行优化设计。将优化参数用于实际试模,物理试验和模拟结果较吻合,证明了数值模拟的可靠性。 相似文献
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采用模拟退火算法优化基于加权平均法的拉丁超立方设计,获得了拉延筋阻力样本。采用Dynaform对翼子板成形进行仿真,以最大增厚和最大减薄作为输出目标,采用改进的粒子群优化BP算法,建立拉延筋映射模型,与单纯采用PSO-BP建立的映射模型进行对比,预测精度大幅提高。采用粒子群算法对映射模型进行优化,得到最优拉延筋阻力,采用非线性函数优化方法求得最优的拉延筋几何参数。采用等效拉延筋阻力模型,避免了有限元网格的重划分和采用真实拉延筋带来的计算效率低的问题,成形效果图说明了采用该方法可以获得较好的最优拉延筋几何参数。 相似文献
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基于有限元分析的覆盖件拉延筋设计与优化 总被引:1,自引:0,他引:1
结合等效拉延筋模型,采用基于有限元逆算法的三维有限元分析软件,对汽车后窗内板的拉延成形进行模拟。在确定合理的等效拉延筋阻力后,通过适当的优化算法对拉延筋的真实几何结构进行优化设计。并通过UG二次开发技术,获取优化的拉延筋几何参数和位置,在拉延件上生成真实的拉延筋模型。 相似文献
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提出了基于迭代学习控制模型的覆盖件模具拉深筋优化算法,极大地提高了优化效率。利用成形状态函数,成形质量函数和学习律函数构建工艺参数优化的迭代控制模型。将该模型应用到拉深筋阻力值优化中,利用有限元模拟代替很难显示表达的状态函数,预测给定工艺参数方案下板料成形后的应力应变状态。根据单元的应变状态,定义拉深筋线段的局部缺陷程度为成形质量函数,评价拉深筋周围的成形质量好坏。学习律函数不仅参考拉深筋段周围的成形质量偏差确定拉深筋阻力值的改变量,同时还能智能更新学习增益修正拉深筋阻力值的改变幅度,加快了优化收敛速度。通过门内板的算例,证明了该拉深筋优化算法的快速性和实用性。 相似文献
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Fuh-Kuo Chen Jia-Hong Liu 《International Journal of Machine Tools and Manufacture》1997,37(4):409-423
In order to facilitate the three-dimensional finite element analysis for the stamping process, an equivalent drawbead model was adopted to simulate the restraining effects produced by the real drawbead. In the present study, the restraining force exerted by the real drawbead was first computed by the finite element simulation, and the optimum pseudo drawing speed and mesh sizes for both the drawbead and sheet metal employed in the computation were determined through a systematic approach. The computed restraining force was then assigned to a regular mesh which replaced the mesh of the real drawbead. This constitutes the equivalent drawbead model, which avoids the extremely fine mesh required to describe the deformation of sheet blank in the drawbead area. In consequence, a huge amount of computation time can be saved. The accuracy of the finite element simulations using the equivalent drawbead model was validated by both the experimental data and the theoretical predictions. 相似文献
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汽车覆盖件成形中拉延筋约束力的模拟计算 总被引:4,自引:1,他引:4
通过拉延筋基本单元模拟试验,对板料在筋内变形机理、压边力和筋的几何参数对拉延筋约束力的影响规律,拉延筋约束力随模具包角变化的规律及板料拉过筋时的变形情况进行了研究,建立了拉延筋约束力计算模型。 相似文献
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2D elasto-plastic FE simulation of the drawbead drawing process 总被引:1,自引:0,他引:1
Y. Y. Yang Z. H. Jin R. F. Wang Y. Z. Wang 《Journal of Materials Processing Technology》2002,120(1-3)
The drawing process including the locking and pulling phase under a drawbead of circular and rectangular section shape is simulated by means of a static-implicit FE code developed by the authors for 2D elasto-plastic simulation of sheet metal forming. The influence of the main bead geometrical parameters on the binder hold down force (BHDF) and drawbead restraining force (DBRF) is analyzed. The deformation law and loading characteristics of the sheet around the drawbead are studied during the two sequential phases. The calculated results show a good agreement with the experimental data. The investigation lays a foundation for setting up an applied drawbead model in the future 3D simulation of drawbeads. 相似文献
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Drawbeads in sheet metal forming 总被引:4,自引:0,他引:4
M. Y. Demeri 《Journal of Materials Engineering and Performance》1993,2(6):863-866
Drawbeads are used to control the flow of sheet metal into the die cavity during stretch-draw forming of large panels. They
prevent wrinkling in formed panels, reduce the blankholder force, and minimize the blank size needed to make a part. Drawbead
restraining forces (pulling forces) and failure locations in the formed sheets are usually evaluated by using drawbead simulation
tooling. In this article, a drawbead simulation apparatus is used to assess the influence of variation in material, bead penetration,
and fric-tion conditions on the drawbead restraining force. Results from the test can be used as input for sheet metal forming
simulation programs. 相似文献
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Equivalent drawbead models associated with drawbead types, with which the geometrical modeling of drawbeads can be replaced
in a numerical simulation of the stamping process, are introduced. The accuracy of the equivalent drawbead models rapidly
computing the drawbead restraining and opening forces, based on the hybrid membrane/bending method accommodating Barlat’s
anisotropic yield function for the plane stress state and the modified Chaboche model considering the Bauschinger effect and
transient behavior under the plane strain condition, is verified by comparing the equivalent drawbead forces with those obtained
from the finite element simulation. Moreover, the drawbead forces computed by equivalent drawbead models are employed in a
finite element simulation of the automotive fender stamping process, from which the effectiveness and applicability of equivalent
drawbead models are observed by comparing strains and draw-ins with those measured in the tryout panel. 相似文献