内螺纹铜管滚珠旋压成形有限元分析

根据金属塑性成形原理和滚珠旋压成形的工艺特点,利用MSC.Mentat/Marc软件建立了内螺纹铜管滚珠旋压工艺的三维弹塑性非线性有限元模型.模拟了管坯从开始接触到变形稳定阶段内螺纹铜管的成形过程,探讨了铜管成形过程金属流动的位移规律及应变分布.     

内螺纹铜管滚珠旋压三维有限元模拟

内螺纹管滚珠旋压三维有限元模拟中,铜管的网格划分和滚珠加载方式是模拟的关键问题。通过建立简化的六分之一旋转对称模型和采用网格局部重划分技术,成功地模拟和再现内螺纹管滚珠旋压成形过程。对模拟结果的对称面变形的情况分析论证了模型简化的合理性和正确性。对模拟的应变分布和速度分布分析说明,齿成形的多道次局部成形规律。从计算的模具载荷变化情况分析了模具的使用寿命。     

微沟槽热管充液旋压成形实验研究

对微沟槽热管充液旋压成形工艺进行了研究,通过试验对影响充液旋压成形加工的三种关键性因素进行了研究与分析.结果表明,在影响充液旋压加工沟槽式热管的三种因素中,旋压当量直径和刀具与滚珠间相对位置主要影响热管内微沟槽形状和尺寸大小,如槽深、槽宽和深宽比;刀具与滚珠间相对位置和拉伸速度影响充液旋压加工过程中铜管是否被拉断;拉伸速度对热管表面粗糙度影响很大.     

内螺纹翅片铜管高速旋压拉伸成形的研究

对内螺纹理片铜管的高速旋压拉伸成形加工机理进行了系统研究，分析了加工过程及参数。试验结果表明，齿深量随坯管与内螺纹管壁厚的比值及材料塑性的增加而逐渐增大，但外表面粗糙度随之变差；拉速与旋速的比值增大会导致外表面粗糙度变差，但随着旋速提高，其影响变小。     

杯形薄壁矩形内齿旋压成形数值模拟与试验

为研究主要工艺参数对齿轮成形状况的影响规律,并为参数优化和工艺设计提供依据,基于MSC.MARC有限元分析软件,对杯形薄壁矩形内齿旋压成形工艺过程和工艺特点进行分析,从而获得旋压成形时变形金属沿轴向、径向和切向的流动规律。结合工艺试验,定量地研究了主要工艺参数对齿高成形的影响规律,并对试验中出现的各种典型缺陷进行分析,提出有效的预防和改进方法。提出将包括轮齿的切向和轴向尺寸均匀程度等作为旋压成形内齿零件的主要质量评价指标。模拟和工艺试验结果表明,矩形内齿旋压成形时,压下量在一定范围内对齿高的成形影响显著,进给比对齿高成形影响不大。当工艺参数选择不当时,可能出现表面隆起或破裂、轮齿周向错移、周向高度不均和齿槽撕裂等缺陷。     

空气调节器用换热器高效传热内螺纹铜管研究

空调器的高效节能和小型化趋势促进了换热器所用传热管的传热强化,高效传热内螺纹铜管得到了广泛应用。内螺纹铜管与普通铜管相比换热效率明显提高,被广泛用于空调器的蒸发器和冷凝器中。介绍了内螺纹铜管的特点优势,阐述了其齿型及齿形参数,同时简述了内螺纹铜管的结构、性能与成形工艺,并且指出了内螺纹铜管的发展趋势。     

滚珠旋压成形工艺及研究现状

滚珠旋压技术作为旋压成形方法的一个分支,具有工艺方法简单、材料利用率高、产品成本低等优点,已成为国内外成形加工方法研究的热点。介绍了滚珠旋压成形工艺的原理、工艺参数及工艺特点,并对国内外研究现状进行了分析。     

多V型皮带轮旋压成形过程的有限元分析

基于动力显式有限元软件,以电磁离合器皮带轮为侧,开展了两个工序的旋压成形工艺的数值模拟,研究了旋压成形过程中材料变形情况,对成形件的应力应变分布进行了分析。模拟结果表明：采用旋压成形工艺,通过设置合理的进给量、芯模转速等参数,成形出的零件不仅形状和尺寸满足要求,而且芯模和旋轮所受载荷不大,旋轮最大载荷为540kN,芯模最大载荷为19kN。该研究对旋压带轮的非线性有限元分析和实际生产中设备的选择具有一定的参考和实用价值。     

新型内螺纹铜管旋压成型装置

内螺纹铜管旋压成型装置在我国处于起步阶段,现介绍其原理、结构及作用,该装置与配套装置构成高速旋压系统。拉制内螺纹铜管的速度上原来的２ｍ／ｍｉｎ提高到１５－２０ｍ／ｍｉｎ,生产效率提高了７－１０倍。     

旋压成形带内筋筒形件的工艺研究及数值模拟

针对旋压成形带内筋筒形件的工艺进行试验研究和数值模拟.依据实际试件的尺寸及成形情况对边界、接触、摩擦以及空间运动等条件进行确定.建立三维有限元数学模型,分析在不同壁厚减薄率和旋轮进给率等工艺参数下内筋的成形情况和应力、应变及旋压力的变化规律.对试件在成形试验时出现的表面剥离、裂纹等缺陷进行预测和初步分析,可提高工作效率并降低研发成本,为进一步深入研究带内筋筒形件旋压工艺的成形机理和变形特点打下了良好基础,为优化工艺参数提供了有效方法和可靠依据.     

ANALYSIS OF MECHANICS IN BALL SPINNING OF THIN-WALLED TUBE

Ball spinning is applied to manufacturing thin-walled tube with high precision and high mechanical properties. On the basis of plastic mechanics, by simplifying ball spinning of thin-walled tube as plane strain problem, slab method is used for the purpose of calculating the contact deformation pressure. The spinning force components, the torsional moment, the deformation power and the deformation work are calculated further as well. The influence of the two important process parameters such as the feed ratio and the ball diameter on the spinning force components is analyzed in order to further control the spinning force components by regulating the two process variables during the ball spinning process. The stress and strain state in deformable zone as well as mechanics boundary conditions in ball spinning are obtained. The effect of the three spinning force components on the formability of the spun part is analyzed and validated through the ball spinning experiments. The theoretical and experimental results show that the radial spinning component plays a significant role in ball spinning of thin-walled tube, and the mechanics situation in backward ball spinning contributes to enhancing the plasticity of the metal material, but that in forward ball spinning contributes to advancing the axial flow of the metal material.     

Finite element simulation and experimental investigation on the forming forces of 3D non-axisymmetrical tubes spinning

3D non-axisymmetrical tube (NAT) spinning is a kind of new spinning technology, which breaks through the restriction that only axisymmetrical hollow parts could be produced by traditional spinning technology. The research on the spinning force aims to optimize the machine design and the processing parameters selection. The neck-spinning process of the 3D NAT is simulated by 3D elastic–plastic finite element software, MARC. The characteristics of the neck-spinning force of 3D NAT are compared with that of the axisymmetrical tube (AT) spinning. The effect of the main forming parameters, such as offset amount, oblique angle, nominal reduction of blank radius, feed rate and path direction, on the spinning forces have been studied theoretically and experimentally. It shows that during 3D NAT spinning, the spinning forces varies periodically with the revolution angle of the roller around the blank; the spinning force during backward path spinning is greater than that of forward path spinning. The simulation results conform well to the experimental ones.     

筒形件强力旋压有限元模拟研究

筒形件强力旋压是一种连续的局部复杂变形过程。采用动态显式有限元程序LS-DY-NA3D对筒形件强力旋压进行了三维有限元模拟,对有限元建模关键问题进行了研究,通过试验验证了有限元模型的合理性。以旋压力和最大等效应力为研究对象,研究了工艺参数和模型参数对模拟结果的影响。模拟结果和实验结果具有较好的一致性。     

连续挤压机负载扭矩的模拟确定及实验研究

建立了铝合金扁铝线连续挤压成形的有限元模拟模型,并应用有限元分析软件DE-FORM-3D对铝合金挤压的变形过程进行了三维模拟,获得了铝扁线挤压过程中的挤压轮的负载扭矩的行程曲线,该行程曲线一方面为传动系统、主轴系统的设计及电机选择提供依据,另一方面也是挤压轮预应力设计的基础。     

Experimental study of thickness reduction effects on mechanical properties and spinning accuracy of aluminum 7075-O, during flow forming

Flow forming technology is widely used in the production of the axisymmetric industrial parts. The advantage of flow forming process over other manufacturing methods such as press forming is use of simple tooling, reduced forming loads due to localized deformation, and enhanced mechanical and surface quality of finished parts. In this study, the effects of thickness reduction on the mechanical properties and spinning accuracy are experimentally investigated on 7075-O aluminum tube. A prototype spinning machine has been designed and manufactured. The effects of spinning accuracy, surface roughness, percentage of elongation, yield strength, and the ultimate strength as a function of thickness reduction are experimentally examined. The experimental results show that with increment of thickness reduction, the yield strength, ultimate strength, surface hardness, and crystal refining increase, and on the other hand, it has adverse effect on diameter growth, geometrical accuracy, surface roughness, and percentage elongation of spun tube.     

圆管的弹塑性变形分析及有限元模拟

通过分析厚壁圆管施加外压的受力特点．使用ANSYS有限元软件对厚壁圆管弹塑性变形进行模拟,分析圆管的变形规律和应力、应变分布状况。对液压柔性成形的科研和运用提供有效的帮助。     

ZTC4钛合金筒形件等温挤压工艺分析及模具设计

分析了ZTC4钛舍金材料的成型特性,并用MSC／Superform模拟软件对ZTC4钛合金筒形件成型过程进行了模拟。在基于ZTC4钛合金筒形件成型过程中金属流动应力应变分布规律的基础上,结合ZTC4钛合金对温度敏感的特性,最终得出了ZTC4钛合金筒形件温挤压成型的具体工艺参数及合理的模具设计。     

叶轮半固态挤压锻造过程数值模拟

采用DEFORM3D软件对叶轮的半固态挤压锻造过程进行了数值模拟,获得了叶轮成形的主要参数变化规律.结果表明:半固态挤压锻造法可以完成叶轮的成形;叶轮的成形可分为三个阶段,叶片主要是依靠材料的挤压完成成形的,在叶片成形的中期,坯料内部尤其是叶片根部存在着变形不均匀现象,而在叶片成形后期,挤压力急剧增大,最终挤压力为2 780 kN.     

Bursting failure prediction in tube hydroforming processes by using rigid–plastic FEM combined with ductile fracture criterion

The most common failure in tube hydroforming is the bursting failure due to excessive thinning of large deformation. To evaluate the forming limit of hydroforming processes, the Oyane's ductile fracture integral I was introduced and calculated from the histories of stress and strain according to every element by using the rigid–plastic finite element method. The region of fracture initiation and the forming limit for three hydroforming processes, such as a tee extrusion, an automobile rear axle housing, and a lower arm under different forming conditions are predicted in this study. Also it is shown that the material parameters used in the ductile failure can be obtained from the experimental forming limit diagram. From the results, the prediction of the bursting failure and the plastic deformation for the three hydroforming examples demonstrates to be reasonable so that this approach can be extended to a wide range of practical tube hydroforming processes.