共查询到19条相似文献,搜索用时 187 毫秒
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内高压成形的弯曲轴线多边形空心变截面结构件能够满足减重、节约空间以及提高强度和刚度的要求,使其成为汽车制造业以及航空航天领域的理想结构件.但弯曲轴线多边形截面构件内高压成形的不均匀变形问题是影响开裂及壁厚分布不均匀的一个重要原因.本文以轿车底盘前梁为例,采用实验方法研究了弯曲轴线多边形截面构件内高压成形的不均匀变形问题,分析了各种开裂缺陷产生的原因,给出圆角大小和成形压力之间的关系及成形件的壁厚分布.研究结果表明,弯曲工序引起的壁厚减薄和增厚导致的坯料不均匀以及复杂截面的周向变形不均匀,是导致内高压开裂及壁厚分布不均匀的主要原因,通过合理的预成形形状可以有效控制内高压成形的变形均匀性,成形出壁厚分布均匀的合格零件. 相似文献
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不规则四边形截面管件内高压成形数值模拟 总被引:1,自引:0,他引:1
以不规则四边形截面管件为研究对象,作内高压成形.基于dynaform软件平台,建立了内高压成形有限元模型,利用该模型研究了内压和轴向进给对不规则四边形管材内高压成形的成形形状、角充填情况及壁厚减薄情况的影响规律,分析了管材破裂和起皱缺陷产生的原因.模拟结果显示,适当减小内压力,同时增大轴向进给量,可以有效地防止破裂的发... 相似文献
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复杂空腔构件的焊接双板液压成形(英文) 总被引:4,自引:0,他引:4
以一个弯曲轴线复杂变截面空腔构件为研究对象,设计并加工了周边焊接双板液压成形实验装置。研究板材尺寸和形状、合模力与液体压力相互匹配的加载路径对板材成形性能的影响,得到了避免试件产生缺陷的工艺参数。结果表明:合理的板材形状可以节约材料、降低成本,并避免因胀形变形为主而导致的圆角破裂以及横截面差异较大区域的堆料起皱;加载路径对预成形阶段法兰区板材流动的影响很大。与传统的冲压再焊接工艺相比,采用双板液压成形弯曲轴线复杂变截面空腔结构更容易且效率更高,可以突破内高压成形受管材截面最大膨胀率的限制。 相似文献
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内高压成形技术研究与应用新进展 总被引:5,自引:0,他引:5
介绍近年来在内高压成形机理、工艺、设备和应用方面的最新进展。针对大截面差管件,弯曲轴线异型截面构件和枝杈管3类工艺,给出典型零件缺陷形式、形状精度、壁厚分布和工艺参数的影响。详细介绍了皱纹控制与利用,降低整形压力的方法和内压与轴向力耦合作用下管材的塑性失稳起皱分析。最后给出了研制的典型内高压成形件及在汽车、航天、航空中的应用。 相似文献
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相比板状扭力梁,采用液压成形工艺加工管状扭力梁能够减轻零件重量,提升零件强度、刚度和疲劳性能。分析了管状扭力梁零件的典型截面形状,指出了零件加工难点和成形过程中的主要缺陷。利用有限元仿真分析方法对管状扭力梁成形过程进行数值模拟,分析了成形过程中典型截面的壁厚变化规律,即过渡区域壁厚变化较大,中间区域壁厚变化不明显。在此基础上进行工艺试验。研究结果表明,管状扭力梁液压成形有限元仿真结果与试验结果吻合性好,零件的实际形状与理论设计形状基本一致。 相似文献
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在铝合金阶段变截面八字形型材生产过程中,制品的侧臂间隙、爪板间隙和扩并口尺寸严重影响着整个型材的外形尺寸。在辊式矫直方法中,通过分析影响该制品各部分外形尺寸之间相互变化的规律,选择合理的配辊矫直方法,消除该制品不同的外形缺陷,在生产中取得了好的效果,使变截面型材的质量、成品率和生产效率都有较大的提高。 相似文献
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凝固速度对高铬铸铁M7C3型初生相的影响 总被引:3,自引:0,他引:3
采用液态金属冷却的定向凝固设备,研究了凝固速度对3.35wt%C-27.5wt%Cr高铬铸铁原位生长复合材料初生M7C3型碳化物的影响。结果表明,凝固速度较高时初生M7C3型碳化物为空心或实心的六边形,随着凝固速度的降低,出现了U形和L形M7C3型碳化物;实心六边形、U形和L形初生相M7C3型碳化物横截面的硬度值为HV 2500左右,而空心六边形碳化物的硬度值为HV 1550左右;初生相M7C3型碳化物在定向凝固过程中具有两种生长方向。 相似文献
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板材成对液压成形可以用于制造复杂几何截面的空腔构件,通过合理的工艺加载路径可以实现板材的流动控制。研究非焊接板材成对液压成形工艺以及两个主要工艺参数(合模力和液压力)的影响。通过理论计算研究不同合模力对应的极限液压力,得到极限液压力曲线,揭示不同工艺参数组合对变形行为的影响规律。通过有限元分析和实验研究验证了理论值,结果表明它们之间具有较好的一致性。实验采用2种线性加载路径和1种阶梯型加载路径研究加载路径对变形行为和零件成形性的影响,结果表明采用阶梯型加载路径可以得到很好的成形性。 相似文献
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Modern lightweight construction, especially in the automotive industry, requires more and more complex components, which can be manufactured in one process step using the hydroforming technology. The combination of the tube and double sheet hydroforming is a new forming process, where a tube and two blanks are formed simultaneously in a die cavity, combining the advantages of both hydroforming variants. This paper deals with the fundamental considerations and investigations related to connection between tube and double sheet. The finite element analysis and laboratory trials were used in order to design the shape of the die cavity and to avoid wrinkles, material tearing and the collapse of the tube section during forming. The paper will also illustrate an analytical model for the prediction of the edge shape in the constrained bulging of a rectangular cup together with several technical solutions, which enabled a complete forming of the investigated part. Finally, the definition of a hydroforming material factor based on the analytical model of the hydraulic bulging process enables the right choice of sheets with different material strength and thickness for the hydroforming of hybrid components. 相似文献
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Ahmad Assempour Mohammad Reza Emami 《Journal of Materials Processing Technology》2009,209(5):2270-2276
Hydroforming is one of the new technologies in the manufacturing processes, in which hollow pieces are formed under pressure of a fluid. The basic parameter in this process is the pressure control of the fluid. This article deals with the process of hydroforming of a pair of metal sheets. After obtaining the kinematically admissible velocity field, the pressure equation is obtained by the upper bound analysis. This equation can be applied for each part if the instantaneous geometry of the deformed sheet in the die cavity zone during the process can be analytically expressed. The effects of the parameters of work-hardening, friction and blank size have been taken into considerations. To validate the results of this work a hemispherical part formed in the hydroforming of single-sheet process has been considered. The results obtained by this analysis have been compared with the experimental results. 相似文献
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Discrete layer forming proposed in this study is a hydroforming process which can selectively deform the outer tube to a desired shape without any deformation of the inner tube by piercing small holes in the inner tube. A three-layered tube is assembled from inner, middle, and outer tubes, from either similar or dissimilar materials, and deforms simultaneously when internal pressure and axial feed are applied to the tube. In special working environments, multi-layered tubes with combined material properties, high strength, and corrosion resistance are required to satisfy conflicting performance requirements. The feasibility of proposed discrete layer forming process of three-layered tube was evaluated by a tube hydroforming experiment and process analysis was performed. An optimal loading path to prevent wrinkling around holes was developed by an analytical model and was experimentally verified. The results show that the proposed discrete layer forming process can be successfully applicable to hollow forming of non-axisymmetric multilayered tubes for structural purposes. 相似文献
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This paper presents recent developments of a simplified finite element method called the inverse approach (IA) for the estimation of large elastoplastic strains and thickness distribution in tube hydroforming. The basic formulation of the IA, proposed by Guo et al. (1990), has been modified and adapted for the modeling of three-dimensional tube hydroforming problems in which the initial geometry is a circular tube expanded by internal pressure and submitted to axial feed at the tube ends. The application of the IA is illustrated through the analyses of numerical applications concerning the hydroforming of axisymmetric bulge, made from aluminum alloy 6061-T6 tubing, the hydroforming of square section hollow component and the hydroforming of a free Tee extrusion from welded low carbon steel LCS-1008 tubing. Verifications of the obtained results have been carried out using experimental results together with the classical explicit dynamic incremental approach using ABAQUS® commercial code to show the effectiveness of our approach. 相似文献