共查询到20条相似文献,搜索用时 312 毫秒
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针对轧制差厚板零件在传统拉深成形工艺中易产生成形缺陷的问题,将充液拉深工艺引入轧制差厚板筒形件的成形中,并通过数值模拟技术对轧制差厚板充液拉深成形过程进行了研究。分析了液池压力对轧制差厚板成形性能的影响,并通过正交试验结合灰色理论讨论了不同工艺参数对轧制差厚板成形性能的影响规律。研究表明:充液拉深成形工艺相对于传统拉深成形工艺能够获取成形性能更好的轧制差厚板。随着液池压力的增加,轧制差厚板筒形件最大厚度减薄率呈现先减小后增大的趋势,而过渡区最大移动量逐渐减小,采用10 MPa的液池压力能够获取较小的最大厚度减薄率,并将过渡区最大移动量限制在较低水平。摩擦因数、压边力以及液池压力对于轧制差厚板充液拉深成形性能的影响程度是依次降低的,采用灰色关联分析获取的优化工艺参数组合可以提高轧制差厚板的成形性能。 相似文献
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Farzad Rahmani Seyed Jalal Hashemi Hassan Moslemi Naeini Hamed Deylami Azodi 《Journal of Materials Engineering and Performance》2013,22(2):338-344
In hydromechanical deep drawing (HDD), a chamber of fluid replaces the matrix and the final form of part is determined based on the form of rigid punch. Allowable working zone in this process indicates the applicable range of chamber pressure versus drawing ratio to achieve a rupture-free drawing. In this article, the HDD of the square parts was studied using the finite element method (FEM) and the effect of different parameters of the process such as pre-bulging pressure, chamber pressure, and friction coefficient on the working zone was investigated. The results showed that increasing of the friction between blank and die or blank and blank-holder confines the working zone, while by increasing of the friction between blank and punch, the working zone becomes larger. A study was also carried out using experimental setup for verifying the FEM results. Finally, the numerical results were compared with experimental ones. 相似文献
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Lihui Lang Joachim Danckert Karl Brian Nielsen 《Journal of Materials Processing Technology》2005,170(3):524-535
Sheet hydroforming has gained increasing interest in the automotive and aerospace industries because of its many advantages such as higher forming limitation, good quality of the formed parts and complicated parts can be formed, etc. The main advantage is that the uniform pressure can be transferred to everywhere at the same time. Based on the hydromechanical deep drawing (HDD) with uniform pressure onto the blank, the multi-sheet hydroforming with the very thin middle layer is investigated. Some features of the formed internal, external and middle layers including high drawing ratio, wall thickness distributions, free wrinkling and fracture, etc., are discussed in details. The process parameters’ effect on the forming process and the ways to improve the sheets formability are discussed both for in experiment and simulation. The results from a simulation were in reasonable agreement with those from an experiment. 相似文献
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A. Anil Kumar Satyanarayan Satapathy D. Ravi Kumar 《Journal of Materials Engineering and Performance》2010,19(8):1150-1160
The importance of hydromechanical deep drawing is due to certain advantages over conventional deep drawing such as better formability, reduced number of manufacturing steps, improved surface finish, etc. Due to this, the potential applications of hydromechanical deep drawing have increased in the recent years. In this process, sheet metal parts are formed with the assistance of fluid pressure. The present work addresses the effect of sheet thickness and punch roughness on the formability of interstitial-free steel sheets in hydromechanical deep drawing. Experimental work has been done to study the influence of counter pressure on drawability by varying the sheet thickness and punch roughness. Finite element method has been used to simulate the process, and the results have been found to be in good agreement with the experimental results. It has been found out that the minimum required counter pressure for successful drawing increases with increase in sheet thickness. Drawability of 1.2 mm thick sheet improved with increase in punch roughness. As the punch roughness increases, the minimum required counter pressure decreases because of improved friction holding effect. For the same punch roughness, the minimum required counter pressure increases with increase in draw ratio. 相似文献
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Residual stress developed during the rolling process of tailor rolled blank (TRB) can affect the springback of finished parts considerably. Springback characteristics of unannealed and annealed TRBs were investigated by means of numerical simulation and experiments taking U-Channel as an example. TRBs were annealed by the annealing process (700 ℃, holding time 10 h), then stamping and springback processes of unannealed and annealed TRBs were simulated, and corresponding experiments were also carried out. Effects of the transition zone length, the blank thickness, the friction coeffcient and the die clearance on the springback of TRB were analyzed. The results demonstrate that the springback of TRB annealed at 700 ℃ for 10 h reduces significantly. For unannealed and annealed U-Channels, the springback of TRB U-Channel is in direct proportion to the die clearance and is in inverse proportion to the transition zone length, the blank thickness and the friction coeffcient. Springbacks of the thinner monolithic (uniform thickness) blank, the thinner side of TRB, the thicker side of TRB and the thicker monolithic blank are sorted in descending order. 相似文献
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A. Meyer B. Wietbrock G. Hirt 《International Journal of Machine Tools and Manufacture》2008,48(5):522-531
Deep drawing is a common sheet metal forming process. In most cases, sheets with constant thicknesses are formed. At the end of the previous century, new innovative blank technologies have been established for weight saving purposes. The development of the flexible rolling process is an illustrating example for this progression. By changing the roll gap during rolling, longitudinal thickness transitions are produced. The innovative semi-finished product, which is produced in this manner, is called tailor rolled blank (TRB). Its behaviour and characteristics during further processing, especially in forming, are topics of present research. The main emphasis of this paper is placed on the idea that TRB can be used to increase the maximum deep drawing depth compared to blanks having a constant thickness. This can be realised by “weakening” certain areas of the blank in a way that the load in failure at critical areas is reduced. To ensure weight saving in addition to increasing the maximum deep drawing depth, the maximum sheet thickness of the TRB is equal to the constant thickness of the other blanks. The concept is first analysed with the help of numerical simulations and then verified by experimental work. 相似文献
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反胀压力对铝合金球底筒形件充液拉深过程的影响 总被引:4,自引:1,他引:3
充液拉深工艺是一种先进的板材柔性成形方法。结合航天部件的实际需求,通过数值模拟的方法,对5A06铝合金球底筒形零件的初始反胀充液拉深成形过程进行了研究。应用基于LS-DYNA3D内核的动力显示分析软件eta/Dynaform5.5,分析了液室初始反胀压力与液室压力对零件壁厚分布以及起皱、拉裂等缺陷的影响规律,讨论了反胀压力与液室压力的匹配关系,得到了合理的加载区间。结果表明,采用优化的初始反胀压力和液室压力耦合加载条件,可以有效的抑制零件球底部的过度减薄,控制悬空区的内皱,提高零件成形质量。 相似文献