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《Journal of Materials Processing Technology》2014,214(9):1820-1827
Continuous roll forming (CRF) is an effective process to manufacture swept surface parts of sheet metal. The forming tool in CRF is a pair of small-diameter bendable forming rolls, a swept surface is formed continuously after the rotating rolls sweep out the whole sheet metal blank. The two bent rolls and the non-uniformly distributed roll gap along the rolls’ length make the sheet metal bent in longitudinal and transverse directions simultaneously, the cross-section curve of the formed swept surface is controlled by the curved profile of the forming rolls and the spine curve is controlled by the differential elongations of sheet metal generated by roll gap. In this paper, a necessary condition for the formation of a swept surface is proposed and analyzed, the parametric equations of the formed surface in CRF are derived and the method to determine the roll gap for forming a given swept surface is presented. The numerical simulations and analyses on the CRF processes demonstrate the validity of the presented theoretical models. The experimental and measured results show that the formed surfaces are in good agreement with the desired surfaces, and swept surface parts with good forming precision can be obtained by CRF process. 相似文献
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《Journal of Materials Processing Technology》2014,214(2):380-389
To realize highly effective and continuous fabrication of three-dimensional (3D) sheet metal parts, a new forming method, surface flexible rolling forming, has been investigated. This method takes only two integral flexible rolls as the forming tool. In the forming process, a non-uniform elongation in the rolling direction and a bending deformation in the thickness direction occur simultaneously, and finally three-dimensional surface parts are formed. In this work, the basic principle and forming mechanism of surface flexible rolling are studied. A method to calculate the transversal curvature radius of the arc-shaped roll is brought forward, while the feasibility is verified by the explicit dynamic finite element analysis. An experimental device has been developed and the forming experiments have been performed. Typical 3D surface parts including the convex and saddle surface parts have been obtained. Finite element model of surface flexible rolling is established and the effect of forming parameters such as reduction, velocity, bending radius and friction on the surface shape is analyzed. The forming effects including shape errors and thickness changes are studied by the deviation analysis. The results indicate that the formed surface is quite close to the criteria one; the thickness of the parts changes gradually and keeps within a narrow range. The experimental formed parts are measured and the forming accuracy is investigated. The results show that the accuracy is high, and are consistent with the simulation. 相似文献
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基于理想形变理论,研究了金属板料成形的有限元逆算法,并开发了计算程序.采用线性三角形膜单元和厚向异性的刚塑性材料模型,计算了一个带凸缘的方盒形件,并与Dvnaform的一步逆向法和增量法的计算结果进行了比较.实例分析结果表明,在工程允许精度范围内,本文方法能够有效分析零件的成形性能.由于该方法计算速度快,所以可用于零件... 相似文献
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Jun-Song Jin Lei DengXin-Yun Wang Ju-Chen Xia 《Journal of Materials Processing Technology》2012,212(11):2247-2254
A new rotary forming process used to thicken the rim of a disc-like part was proposed. The paper details the results, design and manufacture of the corresponding apparatus. The center point of a ring roller moves around the axis of a stationary work-piece in a plane spiral locus, like a rounding hula hoop. Thereby, the rim of stationary work-piece is rolled and thickened. A design rule for the rotary thickening process of the disc-like part was proposed, and a formula for calculating the feeding force of the roller was deduced. Both the design rule and the formula were verified by the results of experiment and finite element simulation. The forming and flow law during the thickening process were also illustrated. 相似文献
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Two-step method of forming complex shapes from sheet metal 总被引:2,自引:0,他引:2
Sergey F. Golovashchenko Nicholas M. BessonovAndrey M. Ilinich 《Journal of Materials Processing Technology》2011,211(5):875-885
A two-step method of forming a part and a method of designing a preform shape are being discussed. The part may be formed from lightweight material to an extent that would normally exceed the forming limits of the material if the part were attempted to be formed in one-step conventional stamping die. Critical areas including deep pockets and sharp radius areas of the final part are formed from a preform or intermediate shape part. The first forming step can be conducted by variety of sheet metal forming methods; the preformed blank is further formed in a fluid pressure forming process to a final part shape wherein broad radius areas and pockets of accumulated metal of the preform are formed into deep pockets and sharp corners of the final shape. Electrohydraulic forming technology is employed for the second forming step. 相似文献
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Investigation into a new hybrid forming process: Incremental sheet forming combined with stretch forming 总被引:3,自引:0,他引:3
B. Taleb Araghi 《CIRP Annals》2009,58(1):225-228
Asymmetric incremental sheet forming (AISF) is a process for the flexible production of sheet metal parts. In AISF, a part is obtained as the sum of localised plastic deformations induced by a simple forming tool that moves under CNC control. Three main problems exist in AISF: material thinning, geometric accuracy and the process duration. These limits restrict the range of applications of AISF. This paper focuses on a new hybrid process, the combination of AISF and stretch forming. First results are presented that show the positive impact of this hybrid process on the process limits. 相似文献
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将拉延筋模型引入到板料成形动力显式有限元分析中,并以汽车前照灯矩形反光镜为应用实例,对其拉延成形过程进行了模拟。 相似文献
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The inverse finite element approach (IFEA) was derived from ideal forming to predict the development blank of sheet metal and the thickness strain distribution according to the geometry of final product. The flange portion of stamping product under blank-holder is a free parameter that is mostly dependent on the shape of the initial flat blank. Based on the IFEA, this paper proposed a node relocation technique to estimate the influence of flange shape and evaluate the final geometry and thickness strain distribution from the prescribed flat blank. The applications of the IFEA cover the backward and forward evaluations: from given product to initial blank and from given initial blank to final product. Those applications make the design of sheet metal forming easy and fast. A door-like product experiment confirmed that the precision of the IFEA satisfied the manufacturing requirement. 相似文献
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金属板料成形工艺CAD/CAM智能化集成研究 总被引:2,自引:0,他引:2
根据现行发展状况,探讨了金属板料成形CADCAE智能化集成的必要性和可行性,分析了其中要解决的一些关键技术,提出了实现CADCAE智能化集成的方法。 相似文献
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Advanced polymers offer at the present time concrete possibilities in reducing the product development time and production
of prototypes and small series of sheet metal parts. However, the applicability of such materials requires different approaches
in comparison to conventional materials for sheet metal forming dies. This paper presents investigation results dealing with
tribological and tool design aspects for the use of polymeric materials in sheet metal forming. Friction and wear of sheets
with different surface topologies have been investigated. A new test method for measuring polymer/sheet wear is presented.
A coupled simulation model for the production of a test geometry aimed specifically at the investigation of die deformations
and loads is presented. The behaviour of two polymeric materials by forming the test geometry has been simulated and the maximal
loads and deformations during the process have been quantified. Simulation results have been subsequently validated in experimental
testing. 相似文献
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限制自由度单元及其在板料成形过程数值模拟中的应用 总被引:2,自引:0,他引:2
根据板料成形过程的特点,提出一种用于板料成形分析的新单元模型-三维限制自由度单元模型,这种单元既没有膜单元不能考虑横向剪应力的遗憾,也不受壳单元对于局部大的限制毛坯后机加工同时克服了体单元解决板结构问题时刚度矩阵奇异的缺点。 相似文献
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