共查询到19条相似文献,搜索用时 527 毫秒
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传统汽车前梁的制造一般是板料冲压成形,它的缺点是成形工序多,模具结构复杂。内高压成形汽车前梁具有工艺简单,生产费用低,成形零件强度与刚度高的优点。采用有限元分析方法对汽车前梁内高压成形过程进行了模拟分析,研究了预弯曲形状和内高压压力对零件成形质量的影响。结果表明:坯料形状对零件胀形质量有重要影响,完全预弯成形后零件胀形质量较好;内高压压力过大会使零件破裂,过小会造成胀形不足;当内高压压力为70 MPa时,可成形出质量较好的零件。 相似文献
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《塑性工程学报》2016,(6):30-36
基于有限元分析软件eta/DYNAFORM,对汽车前指梁的弯曲成形、预成形及内高压成形工艺过程进行了数值模拟。在弯曲成形工步中,研究了管坯各个弯曲位置在相同弯曲半径、不同弯曲角度下的壁厚分布;在预成形工步中主要分析了预制坯形状对前指梁内高压成形的影响;在内高压成形工步中,研究了优化后的预制坯形状对最终成形零件成形缺陷的影响。基于有限元模拟结果,分别进行了弯曲成形、预成形和内高压成形试验。研究结果表明:预制坯形状是决定前指梁内高压能否顺利成形的重要因素;通过改变预成形模具的结构形式,可以得到合理的预制坯形状,避免内高压成形过程中缺陷的产生。实际成形试验结果与数值模拟结果基本一致。 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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对内螺旋状零件的冷挤压成形过程进行数值模拟,系统地研究了摩擦系数、螺旋角和挤压角等因素对内螺旋状零件冷挤压成形过程中凸模所受挤压力和成形缺陷的影响,并对挤压成形工艺参数进行了优化.研究结果表明:摩擦系数、螺旋角和挤压角等因素对内螺旋状零件冷挤压成形过程中挤压力存在显著的影响.随着摩擦系数的增加,挤压力呈线性增加;随着螺旋角和挤压角的增加,挤压力呈非线性增加.摩擦系数和螺旋角等对内螺旋状零件的冷挤压成形缺陷影响较大,而挤压角的影响较小.采用优化后的工艺参数对内螺旋状零件进行了冷挤压成形实验,获得了合格的制件.本文的研究结果为内螺旋状零件的冷挤压成形提供了工艺指导,具有实际的应用价值. 相似文献
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黎永杰 《锻压装备与制造技术》2011,46(3)
对复杂形状空心构件内高压成形工艺进行了数字模拟研究。采用有限元模拟,对矩形截面空心零件弯曲部位在内高压成形过程中产生起皱、破裂等缺陷进行了分析;针对矩形截面空心件弯曲部位,提出采用椭圆截面充液预成形的方法,控制起皱、破裂缺陷的产生,成形质量较理想。并通过试验进行了验证,采用较低压力可以改善内高压成形过程中材料的分布、提高材料的成形极限、控制缺陷产生并提高产品质量。 相似文献
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Cold spray is a coating deposition method in which the solid particles are accelerated to the substrate using a low temperature supersonic gas flow. Many numerical studies have been carried out in the literature in order to study this process in more depth. Despite the inability of Johnson-Cook plasticity model in prediction of material behavior at high strain rates, it is the model that has been frequently used in simulation of cold spray. Therefore, this research was devoted to compare the performance of different material models in the simulation of cold spray process. Six different material models, appropriate for high strain-rate plasticity, were employed in finite element simulation of cold spray process for copper. The results showed that the material model had a considerable effect on the predicted deformed shapes. 相似文献
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针对薄壁筒形件内外齿加工效率低、成本高、精度低等问题,采用筒形件作为坯料,开展了旋挤复合成形工艺研究。分析了旋挤复合成形工艺相关运动规律、材料流动特性;通过理论计算及数值模拟确定相关成形工艺参数;然后加工相关工装,成形出高精度薄壁内外齿筒形件,并对相关工艺参数及数值模拟模型进行了验证。研究结果表明,旋挤复合成形工艺可实现高精度薄壁内外齿零件的高效制造;且相关工艺参数合理可靠;建立的数值模拟模型可对成形中材料流动及回弹特性准确预测;所得成果为此类零件旋挤成形工艺的开发提供了相关依据。 相似文献
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从实物断面、金相组织方面分析了Φ140 mm自动轧管机轧辊断裂的原因.结果表明:由于轧辊的化学成分中S元素严重超标和基体组织不正常(球化率低,渗碳体数量过高等),是导致轧辊机械性能显著下降,造成轧辊断裂的主要原因. 相似文献
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Juergen Lenz Ravi K. Enneti Valmikanathan Onbattuvelli Kunal Kate Renee Martin Sundar Atre 《JOM Journal of the Minerals, Metals and Materials Society》2012,64(3):388-392
Silicon nitride has been the favored material for manufacturing high-efficiency engine components for transportation due to
its high temperature stability, good wear resistance, excellent corrosion resistance, thermal shock resistance, and low density.
The use of silicon nitride in engine components greatly depends on the ability to fabricate near net-shape components economically.
The absence of a material database for design and simulation has further restricted the engineering community in developing
parts from silicon nitride. In this paper, the design and manufacturability of silicon nitride engine rotors for unmanned
aerial vehicles by the injection molding process are discussed. The feedstock material property data obtained from experiments
were used to simulate the flow of the material during injection molding. The areas susceptible to the formation of defects
during the injection molding process of the engine component were identified from the simulations. A test sample was successfully
injection molded using the feedstock and sintered to 99% density without formation of significant observable defects. 相似文献
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The flow behavior of feedstock for the tungsten alloy powder in the mold cavity was approximately described using Hele-Shaw flow model. The math model consisting of momentum equation, consecutive equation and thermo-conduction equation for describing the injection process was established. The equations are solved by the finite element/finite difference hybrid method that means dispersing the feedstock model with finite element method, resolving the model along the depth with finite difference methgd, and tracking the movable boundary with control volume method, then the pressure equation and energy equation can be resolved in turn. The numerical simulation of the injection process and the identification of the process parameters were realized by the Moldflow software. The results indicate that there is low temperature gradient in the cavity while the pressure and shear rate gradient are high at high flow rate. The selection of the flow rate is affected by the structure of the gate. The shear rate and the pressure near the gate can be decreased by properly widening the dimension of the gate. There is a good agreement between the process parameters obtained by the numerical simulation and the actual ones. 相似文献
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Directed energy deposition (DED) is an additive manufacturing technology where a moving energy source creates a meltpool on the surface of a substrate into which feedstock material is deposited to form the final part geometry. Maintenance of the meltpool during deposition requires very high intensity energy flux to overcome thermal losses to the surroundings and substrate. Trochoidal toolpaths are investigated using numerical simulation and DED experiments as a means of increasing the efficiency of the DED process. Trochoidal laser motion during DED was found to increase the material addition rate by 17% and powder catchment efficiency by 15%. 相似文献
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With the rising interest in lightweight construction, the usage of high strength steel has increased remarkably during the last years. Unfortunately, there is manufacturing problem: high strength steel has a higher occurrence rate of cracks than mild steel. The Gurson-Tvergaard-Needleman (GTN) model is used to precisely predict the occurrence of cracks in roll forming. The flow stress and the GTN material parameters are identified using a load-displacement curve obtained from tensile test. In detail, the material parameters that have to be determined were selected and based on this 3-level orthogonal array is made. The coefficients of the objective function are derived using the response surface method with the orthogonal array based on the simulation results. The material parameters are obtained by minimizing the objective function and determined by comparing the simulation and test results. The reliability of the material parameters determined by the tensile test increased through cross-validation using the bending test. The roll forming simulation with the determined parameters is fulfilled, and the experiments are performed to determine the occurrence of micro-cracks according to bending angles. Micro-cracks are quantified by comparing the void volume fraction (f) from the GTN model, and the micro-cracks on the surface are measured using a scanning-electron-microscope. 相似文献