共查询到19条相似文献,搜索用时 156 毫秒
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摩擦系数对薄壁T型管内高压成形的影响 总被引:1,自引:0,他引:1
为探究不同摩擦系数对成形T型三通管支管高度、壁厚差、最小壁厚及关键部位的壁厚变化的影响,利用DYNAFORM软件,对薄壁T型三通管内高压成形过程进行了模拟,研究了在0.01~0.2范围内6种不同摩擦系数情况下,支管高度和壁厚的变化,分析了最小壁厚和关键点随时间的变化情况,并选用4种不同润滑剂进行实验验证。结果表明:成形T型三通管的合适的摩擦系数区域为0.06~0.125,摩擦系数过大或过小都会影响T型三通管的成形效果。依据模拟结果,对薄壁铝合金管材进行成形实验,研究发现实际管材成形效果与DYNAFORM模拟结果较为吻合,验证了数值模拟结果的合理性。 相似文献
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对薄壁Y型三通管的内管压成形进行研究。通过轴向补料,管材可以被推入模腔从而获得更高并且相对减薄率小的支管。但是Y型三通管的导向区较长,在内压作用下管材和模具之间会产生较大的摩擦力,使得材料难以流入支管。提出了采用多段式冲头用来改变导向区的内压分布并且减小导向区的摩擦力的方法。对铝合金Y型三通管进行内高压成形实验,采取两种方案,分别使用传统冲头和多段式冲头进行对比。对壁厚分布和减薄率分布进行研究,并对使用不同冲头的结果进行对比。 相似文献
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内高压成形理论与技术的新进展 总被引:8,自引:0,他引:8
介绍哈尔滨工业大学在内高压成形基础理论、关键技术及工业应用等方面取得的重要进展。在基础理论方面,利用平面应力屈服椭圆描述典型内高压成形过程中应力状态及壁厚变化趋势;揭示变径管内高压成形过程中壁厚分布规律以及多边形截面环向的壁厚分布特点;指明整形阶段圆角充填时存在极限圆角半径;发明了用于测量管材环向力学性能的管材环向拉伸实验方法。在工艺关键技术方面,针对航空航天领域对大直径薄壁复杂管件的需求,发明了Y型薄壁三通管两步成形方法、双层管充液弯曲方法,试制出超薄Y型三通管、整体不锈钢进气道及弯管零件。在工业应用方面,研制了合模力最大达55 MN的工业生产用大型内高压成形机,并成功地用于轿车底盘零件大批量生产。 相似文献
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空心双拐曲轴内高压成形数值模拟 总被引:1,自引:0,他引:1
应用动态显式有限元法对空心双拐曲轴的内高压成形过程进行了模拟分析,研究了加载路径对内高压成形的影响,指出了在加载曲线中存在着最佳成形区间,成形压力小于20MPa时,管坯产生起皱,成形压力大于32MPa时,管坯发生开裂,只有合理的应用加载路径,成形压力介于20MPa与30MPa之间,使轴向进给量可以正好补偿径向的变形量才能获得壁厚较为均匀的合格零件。 相似文献
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《Journal of Materials Processing Technology》2014,214(7):1341-1351
In this paper, in order to explore the deformation behavior of double-sided tube hydroforming in square-section die, effect of external pressure on the critical effective strain was theoretically analyzed firstly. And then a special experimental setup was designed for double-sided tube hydroforming in which the difficulty of simultaneous loading was overcome using two independent intensifiers and servo controlling while the sealing of external pressure was guaranteed by the O rings assembled in the interfaces of mandrel/base plate and outer cylinder/base plate. Furthermore, 5A02-O aluminum alloy tubes with outer diameter of 63 mm and thickness of 2 mm were investigated under different external pressures varying from 0 to 80 MPa. At the same time, numerical simulation was conducted using the Abaqus/Explicit software. It is shown that increasing of external pressure has an effect on the fraction of grain boundaries, the number and size of the microvoids and the microhardness in the transition zone, and thus increases the critical effective strain in the transition zone. It can be concluded that the deformation ability of the transition zone is improved by the external pressure in double-sided tube hydroforming of square-section. This investigation shows that double-sided tube hydroforming is a potential forming method for the fabrication of lightweight hollow structures using the tubes with low ductility. 相似文献
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A new history of internal pressure in the hydroforming processes of tubes is developed to attain high formability. The effect of improvement of formability by the oscillation of internal pressure in a pulsating hydroforming process of tubes is examined using both finite element simulation and experiment. The deformation behaviour during the hydroforming is greatly affected by the oscillation of internal pressure. For a monotonic history of small internal pressure, the wrinkling was caused by insufficient bulging, whereas the necking and bursting occurred for a monotonic history of large internal pressure. The occurrence of these defects can be avoided by oscillating the internal pressure in the pulsating hydroforming. The improvement of formability in the pulsating hydroforming is due to both low pressure and oscillation of pressure. The effects of the amplitude and cycle number of pressure in the pulsating hydroforming on the deformation behaviour are investigated. It is found the oscillation of internal pressure is effective in preventing the occurrence of defects. 相似文献
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Atsushi Shirayori Sadakatsu Fuchizawa Michiharu Narazaki 《Metals and Materials International》2007,13(2):185-189
Loading paths (hereafter referred as LPs) that consist of internal pressure and axial feeding are important manufacturing
conditions in tube hydroforming. Among the factors that affect LP design, friction between the forming die and tube causes
the most difficulty due to its complicated characteristics. Although there is no friction, a number of issues with LP design
remain. In this study, free hydraulic bulging (hereafter FHB) with internal pressure and axial feeding is investigated. In
FHB, tubes are freely expended without friction. It has been shown that axial feeding affects the circumferential thickness
distribution in the tube periphery. The tubes in this study are straight seamless tubes. Seamless tubes typically have predictable
thickness deviations resulting from their manufacturing processes. In general, the degree of thickness deviation will increase
as the tube expands. A FEM simulator is used to analyze the mechanism of the growth of thickness deviation. 相似文献
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管材内高压胀形的实验研究与数值模拟 总被引:3,自引:0,他引:3
介绍了管材无模轴压胀形的实验,研究表明,适度的褶皱有助于提高成形极限。有限元数值模拟显示,随着内压—轴压匹配模式的改变,内压增长率对褶皱的演化表现出不同的影响效果。针对管坯—模具间摩擦对T型管复合胀形成形性的影响,分别从实验和有限元数值模拟两方面进行了研究。 相似文献