共查询到17条相似文献,搜索用时 374 毫秒
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《塑性工程学报》2017,(4)
为提高波纹管的成形质量以及合理选取胀形工艺参数,基于有限元分析软件ABAQUS模拟304不锈钢双层波纹管液压胀形过程,并利用实验验证了有限元模型的正确性。基于建立的模型,研究了内压力、模具行程、挤压速度和加载路径对波纹管成形的影响。结果表明,影响双层波纹管液压胀形壁厚减薄和波高的主要工艺参数为内压力和模具行程;随着内压力和模具行程的增大,最大壁厚减薄率和波高均线性增大,且内外层壁厚差值增大;过大的内压和挤压速度会导致波高不均匀性增大;降低起波阶段内压力及在成形初期施加轴向进给的加载路径有利于减小波纹管的减薄率。最后,通过双层波纹管的液压胀形实验验证了数值模拟的正确性。 相似文献
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为了解决传统拼焊制造超薄壁不锈钢波纹管弹性差、寿命短、易破裂等问题,采用液压成形技术成形超薄壁不锈钢波纹管件。针对超薄壁不锈钢波纹管件截面形状复杂以及管壁易失稳起皱破裂的成形难点,设计了不同的加载路径。利用CATIA进行建模,使用Dynaform有限元分析软件进行数值模拟。基于波纹管成形过程中的波高与壁厚减薄情况研究了模具间隙、预胀形内压和整形压力对成形质量的影响规律。试验结果表明,对于复杂异形截面的填充,管内压强和轴向进给的增大有利于材料流动进入圆角区域以及管坯与模具的贴合。对于内径Φ50 mm,壁厚0.4 mm的复杂截面波纹管,预胀形内压7.5 MPa,整形压力20 MPa,轴向进给为20 mm为最佳参数匹配。开展了相关试验,验证了模拟结果与试验结果相符,获得的波纹管满足尺寸与性能的需求。 相似文献
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内高压成形技术是一种利用液体作为传力介质,通过控制内压力和轴向推力来达到成形空心零件目的的先进制造技术,在航空、航天、汽车等轻量化领域获得了广泛的应用。管材的内高压成形过程十分复杂,成形结果与诸多因素有关,其中内压力及轴向进给的加载路径及其匹配关系对成形结果影响尤为显著,如何找出诸多影响因素对内高压成形的影响规律并进行合理的优化是内高压成形面临的重要问题。首先利用均匀设计法设计BP神经网络训练样本与检测样本。其次,分析BP神经网络和遗传算法,并进行融合,基于MATLAB语言编写BP神经网络的算法程序及遗传算法程序,对空心双拐曲轴内高压成形加载路径工艺参数进行了优化,得到其最优成形参数。并通过DynaForm软件仿真验证了结果的准确性,从而完成对管材内高压成形加载路径的参数优化,进一步提高了管材内高压成形的成形质量。 相似文献
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以镁合金(AZ31)T形管在150℃的情况下的成形为研究对象,对镁合金管件的内高压成形机制进行分析和有限元模拟,得到镁合金管件内高压成形特性,实现轻量化。通过理论计算得到成形圧力;然后利用有限元软件Dynaform,分析T形管在已得到的压力下,不同轴向进给速度对成形的影响;分析了在相同的内压和轴向进给速度下,不同壁厚对成形的影响。结果表明:镁合金T管在150℃下的最优成形压力为20 MPa,轴向速度为5 m/s,壁厚为1 mm;镁合金的成形需要合适的温度、内压力、轴向推力的合理配合。 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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Optimization of loading conditions for tube hydroforming 总被引:12,自引:0,他引:12
Tube hydroforming is a developing technology with advanced features of lightness and unified part. This study investigates the best possible regulation for loading conditions between the internal pressure and the axial feeding by hydroforming of a T-shape metal tube. Using conjugate gradient method with finite element method, a program module is generated to check the hydroformed tube quality about its thickness uniformity and the geometry accuracy. Thereby, a batch mode and a sequential mode to optimize the loading conditions of the tube hydroforming process are created and investigated. Regarding the tube quality from the simulation results, the hydroforming process, which follows the loading curve generated by the sequential mode, is better than by the batch mode. The optimal loading procedure generated by this article can offer another possibility for engineer by determining the internal pressure and the axial feeding in tube hydroforming. 相似文献
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S.J. Yuan C. Han X.S. Wang 《International Journal of Machine Tools and Manufacture》2006,46(11):1201-1206
An experimental and numerical simulation was conducted to investigate hydroforming of automotive rectangular-section structural components and the results were used as guidelines for some prototypes. The effect of loading path on the failures and thickness distribution was discussed and the reasons were analyzed for the failures, such as bursting and folding. Hydroforming with axial feeding is strongly sensitive to the loading path. Bursting occurs in transition zone in the calibration when the internal pressure increases faster than the axial feeding. Otherwise, folding will take place due to too much axial feeding. There is the maximum thickness at central point of the side of cross-section and the minimum thickness at the transition area. If the n value of the tube material is bigger, the thickness of the final part will be more uniform. By using a petal-like perform section shape, the pressure for forming the transition radii was greatly reduced and components with small radii can be formed with relatively low pressure. 相似文献
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Wrinkling behavior of magnesium alloy tube in warm hydroforming 总被引:1,自引:0,他引:1
In tube hydroforming with axial feeding, under the effect of coupled internal pressure and axial stress, wrinkles often occur and affect the forming results. Wrinkling behavior of an AZ31B magnesium alloy tube was experimentally investigated with different loading paths at different temperatures. Features of wrinkles, including shape, radius and width, were acquired from the experiments, as well as the thickness distribution. Numerical simulations were carried out to reveal the stress state during warm hydroforming, and then the strain history of material at the top and bottom of the wrinkles were analyzed according to the stress tracks and yielding ellipse. Finally, effects of loading paths on expansion ratio limit of warm hydroforming were analyzed. It is verified that at a certain temperature, expansion ratio limit can be increased obviously by applying a proper loading path and realizing enough axial feeding. 相似文献
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Based on the sidewall wrinkling phenomena in hydroforming of thin-walled Tee-joint, an analytical model for tube wrinkling under double side constraints was proposed to calculate the critical wrinkling stress. The effects of stress ratio, diameter-to-thickness ratio and tube material properties on critical condition of sidewall wrinkling were investigated. It is found that the middle of the main tube side wall is the most dangerous position for wrinkling within hydroforming of thin-walled Tee-joint. At a certain internal pressure, the critical wrinkling stress increases with increasing of ratio of hoop stress to axial stress and material strength coefficients, but decreases with increasing of work-hardening exponent and ratio of diameter to thickness. Through the analytical model combining FEM simulation, the critical wrinkling loading path according to the relation between axial feeding and internal pressure was obtained. Experimental results validates that wrinkle can be avoided if the pressure is above the critical wrinkling loading path, otherwise, wrinkle occurs. It is also verified that the analytical model of critical wrinkling stress is reasonable for the thin-walled Tee-joint hydroforming process. 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