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Effect of mandrel on cross section quality of thin-walled tube numerical controlled bending 总被引:7,自引:0,他引:7
The effect of mandrel with the structure of ball and socket on the cross section quality of thin-walled tube numerical controlled (NC) bending was studied by numerical simulation method, combined with theoretical analysis and experiment. Influencing factors of the mandrel include the count of mandrel heads, the diameter of mandrel and its position. According to the principle of NC tube bending, quality defects possibly produced in thinwalled tube NC bending process were analyzed and two parameters were proposed in order to describe the cross section quality of thin-walled tube NC bending. According to the geometrical dimension of tube and dies, the range of mandrel protrusion was derived. The finite element model of thin-walled tube NC bending was established based on the DYNAFORM platform, and key technological problems were solved. The model was verified by experiment. The effect of the number of mandrel heads, the diameter of mandrel and the protrusion length of mandrel on the cross section quality of thin-walled tube NC bending was revealed and how to choose mandrel parameters was presented. 相似文献
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Y. L. Liu Y. X. Zhu W. Q. Dong H. Yang 《Journal of Materials Engineering and Performance》2013,22(1):9-16
Springback is inevitable for thin-walled rectangular 3A21 tube in rotary-draw bending process, and Young’s modulus is a crucial material property parameter affecting springback simulation. Therefore, to improve the springback prediction precision, the variation of Young’s modulus with plastic deformation for 3A21 material is studied through a repeated loading-unloading experiment, and a piecewise linear function is given out to describe the relationship between Young’s modulus and plastic strain, which is considered into a new material constitutive model combined with the Von-Mises yield function and the Swift isotropic hardening rule. Furthermore, a finite element springback prediction model is established by means of this new constitutive model for rotary-draw bending process of thin-walled rectangular 3A21 tube, and its reliability is validated experimentally. Comparisons between simulation results and experimental data show that, the accuracy of springback prediction can be improved significantly by 18.02% when the variation of Young’s modulus is considered. On the basis of the established model, the stress distribution field of thin-walled rectangular 3A21 tube in the whole rotary-draw bending process is obtained and analyzed. 相似文献
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以薄壁Y形管为例,进行Y形管有限元建模。运用Dynaform有限元仿真软件进行内高压成形数值仿真,探讨Y形管成形规律、主要缺陷形式及缺陷产生位置;分析几何形貌参数、摩擦因数和加载路径等工艺参数对成形质量的影响。选取起皱间隙和贴模长度作为逻辑控制输入,评价成形状态;为优化Y形管内高压成形加载路径,将成形过程分为4个阶段进行模糊控制系统设计。结果表明:加载路径优化后,充模效果获得较大提升。将内高压成形工艺和模糊控制系统应用于某汽车排气系统Y形歧管,进行结构改进与成形工艺优化,获得了满足质量的合格零件。 相似文献
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管材数控绕弯回弹实验研究及BP网络预测模型 总被引:1,自引:0,他引:1
回弹是影响管材数控绕弯成形精度的主要因素之一。在EATON VB100弯管机上对直径φ6mm~φ15mm之间的3种管材进行弯曲成形实验后,利用激光测量仪测量回弹角度,整理得到准确、可靠的回弹实验数据作为样本数据。采用最小二乘法对实验数据进行拟合,得到关于弯曲角度和回弹角度的函数方程,同时分析了相对弯曲半径、相对管径和管材性能对管材弯曲回弹的影响规律,根据实验,确定了影响管材弯曲回弹主要工艺参数。综合主要工艺参数对管材弯曲回弹的交叉影响,以实验数据作为样本数据,建立和优化了BP神经网络模型,预测弯曲角度和相对管径对回弹的影响规律,通过实验数据的对比,证明预测BP模型具有较高的精度。 相似文献
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Numerical control(NC) bending experiments with different process parameters were carried out for 5052O aluminum alloy tubes with outer diameter of 70 mm, wall thickness of 1.5 mm, and centerline bending radius of 105 mm. And the effects of process parameters on tube wall thinning and cross section distortion were investigated. Meanwhile, acceptable bending of the 5052O aluminum tubes was accomplished based on the above experiments. The results show that the effects of process parameters on bending process for large diameter thin-walled aluminum alloy tubes are similar to those for small diameter thin-walled tubes, but the forming quality of the large diameter thin-walled aluminum alloy tubes is much more sensitive to the process parameters and thus it is more difficult to form. 相似文献
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薄壁铝合金管小弯曲半径数控弯曲是个多因素耦合、多模具约束下的复杂过程。提出以有限元模拟为基础,基于显著性的工艺参数优化方法,即采用析因因子设计分析工艺参数对成形质量,即最大壁厚减薄率和最大截面畸变变化率影响的显著性,获得影响显著的参数,即管与防皱模间间隙的最优值,并确定其他影响不显著的参数值,包括管与模具间的间隙和摩擦、芯棒伸出量和助推速度。结果应用于规格为d50mm×1mm×75mm和d70mm×1.5mm×105mm(管外径D0×管壁厚t0×弯曲半径R)的铝合金管弯曲,获得了合格的管件。 相似文献
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斜辊矫直作为管材生产的最后一道工序,为达到薄壁细管严苛的精度要求,最优矫直工艺参数的设定至关重要。为解决薄壁细管矫直的难点,以现有的十辊矫直机为基础,设计了十辊薄壁细管矫直的模型,并进行了工艺参数研究。利用有限元软件ABAQUS建立了薄壁细管材矫直的有限元模型,通过分析不同条件下矫直后管材的X、Y方向的直线偏差、径向偏差得出了适合薄壁细管的最佳压弯量及压扁量,以此拟合出公式。根据公式计算了两组不同情况下管材的工艺参数,通过仿真模拟及实验验证了公式的可靠性,为薄壁细管精密矫直机的开发制造提供了理论依据。 相似文献
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Ding Tang Dayong Li Zhongwei Yin Yinghong Peng 《Journal of Materials Engineering and Performance》2009,18(4):369-377
Thin-walled C12200 circular copper tube has been widely used in HVAC (heating, ventilation, air conditioning, and refrigeration)
industry. Rotary draw bending is a versatile and precise method in forming of thin-walled copper tubes. Wall thinning and
sectional fattening are the two main defects that affect tube quality in industrial applications. With traditional die settings,
such as adjusting position or type of the mandrel, one factor usually decreases at the expense of increasing the other. An
assistant equipment, surface booster system, has been recently developed to relieve both defects at the same time. In the
present study, the role of the booster system in the bending process is investigated with finite element simulation. A basic
model of copper tube rotary draw bending is established and validated by experiments. Then, cases of different sets of main
parameters of the booster system are studied. The relationship between loading force, lower displacement, speed of the booster,
and forming characteristics of tube is obtained based on which suggestions about process parameters settings are given. The
results provide a better understanding of the role of the booster system in the improvement of forming quality. 相似文献
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截面扁化是管材弯曲成形过程中不可避免的物理现象,而严重的截面扁化会影响弯管件的合理装配,从而制约其广泛应用。本文建立了考虑收缩应变比和弹性模量变化的钛管数控弯曲成形有限元模型,研究了不同几何条件和不同工艺条件下TA18钛管的截面扁化行为。结果表明:同时考虑收缩应变比和弹性模量变化规律可使截面扁化量发生改变,对变化规律无显著影响。获得了合理的几何、工艺参数范围。为研究TA18钛管的成形预测与控制并最终实现精确成形提供了依据。 相似文献
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冲压板料回弹中的失稳研究 总被引:3,自引:1,他引:3
回弹是材料成型结束后的一个复杂的弹塑性变形过程 ,它直接影响到冲压件的尺寸精度。本文采用随动强化材料模型考虑了Bauschinger效应 ,指出回弹卸载中可能会出现局部失稳的现象 ,并应用有限元方法和能量原理 ,提出了回弹失稳的临界应力计算方法 ,对于提高回弹的计算精度、改善冲压件的产品质量有重要意义。 相似文献
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