共查询到19条相似文献,搜索用时 234 毫秒
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针对A7075-T6型材结构件,利用ABAQUS软件建立π型截面型材拉弯成形有限元模型,对该铝合金型材结构件拉弯成形进行数值模拟,并分析预拉量、补拉量、弯曲半径及摩擦系数的变化对回弹的影响。结果表明:预拉量、补拉量、弯曲半径和摩系数都会影响回弹量,在相对应的变化范围内,回弹随着预拉量、补拉量的增大有明显减小的趋势,而回弹量与弯曲半径和摩擦系数均呈正相关。其中对回弹量的变化影响较为明显的为拉伸量;当预拉量为1%,补拉量为2%,摩擦系数为0. 08,弯曲半径为200 mm时,回弹最小。 相似文献
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飞机Z形型材滚弯回弹实验与研究 总被引:1,自引:0,他引:1
周养萍 《锻压装备与制造技术》2012,(1):76-79
通过飞机Z形型材滚弯回弹的研究,分析了影响飞机Z形型材滚弯回弹的因素。实验证明:板料弯曲的平剖面假设理论、中性层理论对型材零件同样适应。研究结果表明:随着弯曲半径的增大,回弹半径也增大;回弹半径随型材厚度的增大而减小;屈服应力愈高、应变刚模量D值愈大,滚弯回弹愈大;自由弯曲回弹量大,校正弯曲回弹量小;形状复杂、相互牵扯多回弹量小;冷作硬化后回弹量大。 相似文献
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《塑性工程学报》2017,(2)
以宝钢生产的14种规格和牌号的钢板为研究对象,对其V弯成形特性进行了研究,通过单向拉伸实验,获得材料的基本力学性能,分析了试验材料的V弯回弹规律。试验结果表明,材料存在正、负回弹,相同弯曲角度下随弯曲半径增大,回弹量增加且趋向正回弹,在相同弯曲半径下,弯曲角度增大,回弹量减小且趋向负回弹,可通过调整弯曲角度或弯曲模具圆角大小来可合理控制零件回弹;在相同厚度条件下,当材料抗拉强度大于600 MPa时,回弹量显著增大;在相同强度条件下,回弹量随弯曲角度的增大而趋向负回弹,同时随着弯曲半径的变大,回弹量随材料厚度产生的差异趋缓,并趋向正回弹;980 MPa强度级别材料中材料厚度越小,不同弯曲半径下的回弹量差异变大;厚度相同的情况下,QP钢和MS钢的回弹量比DP钢更趋向于正回弹;数值拟合发现,回弹角度随R/T值的增大而增大,且经历一个由负到正的过程。随着弯曲角度的增大,拟合曲线下移且斜率变小,只有当R值足够大时才会出现正回弹。 相似文献
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针对轿车用复杂截面PVC塑料包覆铝型材密封条的三维拉弯成形,采用控制拉伸量的方法,通过选择合理的预拉量、恰当的成形模具截面及型材间填充物,对该截面型材进行了平面和垂直拉弯成形实验,得到了该型材平面和垂直拉弯的半径回弹量。结果显示,垂直拉弯回弹量是平面回弹量的1倍多,实验结果为研制该型材及同类产品拉弯工装模具和工艺参数选择,提供了依据。 相似文献
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针对某一运载火箭大角度型材框,对力控制模式下的拉弯成形进行了模拟及试验研究,模拟分析了拉弯力对成形件应力、应变分布及回弹量的影响规律。模拟结果显示,随着拉弯力增加,型材截面内外侧切向应力差减小,回弹和扭翘变形也减小,但不利的一面是变形量增大,零件壁厚减薄率增加,截面尺寸变化加大,综合考虑,选取合适的拉弯力为97.4 k N。试验分析了拉弯力、第1次拉弯包角及补拉量对零件成形精度的影响规律。试验结果表明,拉弯力和补拉量越大,零件的角度、平度及弧度间隙越小,尺寸精度越高。通过试验,得出了优化的拉弯工艺参数,即拉弯力为105 k N,第1次拉弯包角为65°,补拉量为60 mm。在此参数下拉弯,零件淬火后变形程度较小,扭翘现象较小,回弹量较小,成形出尺寸合格的零件。 相似文献
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拉弯成形工艺具有成形精度高、回弹量小、生产效率高的优点,对轨道列车端顶弯梁进行拉弯数值模拟与成形实验。利用数学解析法计算得到了型材拉弯过程中夹钳的运动轨迹,并定义了型材拉弯过程中典型的成形缺陷。利用有限元模拟对比分析不同选材和工艺参数下成形后零件的应力分布、回弹、截面畸变和空间扭转。研究结果表明:选用ENAW-6005-T4材料可以避免型材拉弯过程中的断裂;采用预拉0.5%和补拉1.5%的加载组合时,型材的卸载回弹量最小;采用1.5 MPa的填充压强可以有效地抑制型材外壁的内凹;改善摩擦条件可以减小成形后的空间扭曲。采用优化后的工艺参数进行了实验验证,测量结果和数值分析规律相吻合。 相似文献
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飞机Z形框滚弯加工数值模拟与分析 总被引:1,自引:0,他引:1
采用大型有限元分析软件ANSYS,对飞机Z形框滚弯及其回弹过程进行三维动态仿真模拟。模拟结果表明,在Z形框滚弯过程中,型材截面的4个角处均存在应力集中现象;随着弯曲半径的增大,塑性应变值减小;塑性应变的最大值出现在受压侧缘条的中部;塑性应变为零的部位基本在Z形框高度的中线处。文章研究了各种因素对Z形框滚弯回弹的影响。研究结果显示,Z形框回弹半径随着弯曲半径的增大而增大,随着型材厚度的增大而减小,随着应变刚模量D值的增大而增大。 相似文献
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H. Li H. Yang F.F. Song M. Zhan G.J. Li 《Journal of Materials Processing Technology》2012,212(9):1973-1987
Stress-relieved Ti–3Al–2.5V bent tube in hydraulic bleeding systems improves the overall performance of advanced aircraft and spacecraft due to its unique high specific strength. However, the high ratio of yield strength to Young's modulus may induce significant elastic recovery after unloading. The precision bending of the high strength Ti-tube (HSTT) depends on the understanding of the springback features and mechanisms. Using the plasticity deformation theory, the explicit/implicit 3D-FE and the physical experiments, the springback behaviors of the HSTT under multi-die constrained cold rotary draw bending (RDB) are addressed. The results show that: 1) The elastic recovery of the HSTT should be characterized by the significant angular springback, the radius growth and the sectional springback; Both the angular and radius springback should be compensated, while the sectional one decreases the cross-section flattening; 2) Among multiple parameters, both the material properties (Young's modulus, strength coefficient and anisotropy exponent) and the geometrical dimensions (bending angle and bending radius) dominate the unloading; Both the angular and radius springback values decrease with the smaller bending radii; The angular springback increases linearly with the larger bending angles, while the radius growth fluctuates little with the increasing of the bending angles at the later bending stages; Both the springback values of the HSTT are far larger than the ones of the 5052O Al-alloy tube and the 1Cr18Ni9Ti tube; The maximum variations of the angular and radius springback with changing of the processing parameters are 78% and 62.5% less than the maximum ones under different material properties and geometrical ones, respectively. 3) A two level springback compensation methodology is proposed to achieve the precision bending in terms of both springback angle and radius. 相似文献
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Effects of Cross-Sectional Ovalization on Springback and Strain Distribution of Circular Tubes Under Bending 总被引:1,自引:0,他引:1
Springback and cross-sectional ovalization are two important defects in the bending formation of tubular parts. In this article, an analytic model considering ovalization is presented to calculate the springback and tangential strain in tube bending. Compared with the calculation neglecting ovalization, the proposed model could better predict the trends of springback angle over bending radius ratio and wall thickness ratio. Moreover, calculation of the tangential strain indicates that the bending deformation is more severe in the middle than at the ends of a bent tube. Through comparison of the results of this model and the calculations neglecting ovalization, it is shown that the effects of ovalization on springback are negligible only if the bending radius ratio and the wall thickness ratio are large enough. Also, the influence of ovalization differs a lot from one material to another. 相似文献
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The purpose of this study is to investigate the springback characteristics of tailor-welded strips in U-draw bending. Two
different welded strips were adopted to compare the effects of weld-line locations on the springback. One was welded along
the centerline of the strip-width and the other was welded along the centerline of the strip-length. To investigate the effect
of different thickness combinations on the springback, the tailorwelded strips were joined by a laser welding process. Three
sheet thickness combinations were assessed, SCP1 0.8 t* SCP1 1.2 t, SCP1 0.8 t* SCP1 1.6 t and SCP1 0.8 t* TRIP 1.0 t. Three punch profile radii of 3, 6, and 9 mm and three die profile radii of 5, 10, and 15 mm were prepared and
three blank holding forces (BHF) of 125 kgf, 250 kgf, and 500 kgf were applied to investigate the effects of punch profile radius (Rp), die profile radius (Rd), and BHF on the springback of tailor-welded strips. With consideration for the thickness of the sheet and the material properties,
the extent of the springback on the sidewall of unloaded sheet shapes increases as the thickness and the yield strength of
the sheet increase in the U-draw bending process. For longitudinally welded strips, the amount of springback of the TRIP steel
sheet in TWB could be reduced through a springback combination of the thinner side and weld-line. For the thinner side (0.8
t) of the centrally welded strips, the deformed shapes after the springback were almost the same regardless of the thickness
com|bination, and the extent of the springback decreased compared with that of non-welded SCP1 0.8 t. Some experimental results
are compared with analytical results obtained by using the finite element method. 相似文献
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工艺参数和材料性能对板料成形回弹的影响 总被引:1,自引:3,他引:1
分析总结了数值模拟中模拟参数(有限无算法、单元类型、材料模型、本构方程、积分点选取、接触和摩擦法则等)对回弹模拟精度的影响。对一细长支腿零件的工艺成形过程进行了数值模拟,研究了工艺参数及材料性能参数(压边力、凸模圆角半径、凸凹模间隙、板料厚度、摩擦系数、材料硬化指数)对工件回弹的影响。回弹角随凸模圆角半径和凸凹模间隙的增大而增大,随压边力、扳料厚度、摩擦系数和材料硬化指数的增大而减小。 相似文献
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以某车身铝合金内板件为研究对象,利用有限元模拟软件ABAQUS建立了翻边及回弹过程的有限元模型。通过优化上弯曲半径R1、下弯曲半径R2、翻边角度α等3个产品特征参数和润滑条件μ、模具间隙T等两个工艺参数,来减小回弹值和降低弯裂风险。结合正交试验和灰色关联的方法将多目标问题转化为单目标问题,得到较优的设计参数指导产品设计,并进行试验验证。结果表明,影响综合目标的主次顺序为:模具间隙翻边角度上弯曲半径下弯曲半径摩擦系数,得到优化后的组合参数为R1=5 mm,R2=9 mm,a=75°,μ=0.1,T=t,采用优化后的参数设计零件,得到的实际零件的回弹在公差范围内且无弯裂缺陷。 相似文献
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以V型件弯曲和回弹过程为分析研究对象,通过对V型件弯曲及回弹过程的有限元数值模拟,分析获得了成形参数对V型件弯曲回弹的影响规律。结果表明:回弹角随弯曲角及材料的硬化系数的增大而增大,随材料的变形程度及硬化指数的增大而减小。 相似文献