共查询到20条相似文献,搜索用时 758 毫秒
1.
2.
3.
《塑性工程学报》2015,(6):71-77
针对大型铝合金曲面零件电磁渐进成形工艺中板料不均匀变形的问题,基于ANSYS多物理场模块建立电磁场-结构场耦合模型,对成形过程进行数值模拟分析,研究电磁成形线圈结构参数对板料变形行为的影响,包括:线圈层数、线圈匝间距、线圈层间距、导线截面积和导线截面形状。研究表明,线圈层数增加,板料变形均匀性降低,而板料的变形量增大,多层线圈有利于提高线圈的强度和使用寿命;线圈匝间距与导线的宽度越接近,板料均匀变形效果越好;矩形导线截面的线圈相对圆形导线截面的线圈使板料变形更加均匀;线圈层间距和导线截面积对板料均匀变形影响不大,但是合理的结构参数可以提高线圈强度。提出了一种非等间距线圈结构,非等间距线圈产生的电磁场和电磁力是不均匀的,在板料半径1/3处受到的成形驱动力较大,而这种不均匀的变形力,进一步改善了电磁成形中板料的变形不均匀性,电磁成形平板线圈能与变形后的板料较好的贴合,使大型铝合金曲面零件电磁渐进成形能通过多次放电连续均匀塑性变形。通过实验验证了线圈结构优化设计的可靠性,实验结果与模拟结果基本一致,误差在12%以内。 相似文献
4.
电磁成形有限元模拟涉及多场耦合作用,其中结构场与电磁场之间的不同耦合方法对模拟结果影响显著。与松散耦合方法相比,顺序耦合方法考虑了板料变形对电磁场的影响,从而能够更精确的描述电磁成形过程。以ANSYS仿真软件为平台,建立板料电磁成形的顺序耦合三维有限元模型。通过不同耦合方法的模拟结果与实验结果对比表明,采用顺序耦合模型得到的板料变形与实验接近,而采用松散耦合模型得到的板料变形明显大于实验值。由此可见,顺序耦合模型是适合于电磁成形模拟的可靠模型。采用顺序耦合模型研究发现,放电电流的加载时间对板料电磁成形中板料变形的影响显著。当取放电时间为电流曲线的1.5个周期时,模拟结果与实验数据吻合最好。综合考虑计算效率与精度,板料电磁成形中放电电流的加载时间取1.5个周期为宜。 相似文献
5.
6.
7.
《塑性工程学报》2013,(6):56-61
镁合金室温塑性较差,温热条件下则表现出良好的塑性。该文对AZ31B镁合金板料匀压力线圈温热电磁胀形过程进行分析,研究温度对镁合金板料电磁胀形高度的影响。结果表明,电流的热效应影响板料的变形抗力。当放电电压较低时,电流的热效应对材料的变形抗力影响不大,在室温至150℃范围内,胀形高度随温度上升而下降;随着放电电压升高,电流的热效应不断增大,热效应对材料变形抗力的影响也逐渐加强,在室温至150℃范围内,胀形高度随温度升高而下降的趋势逐渐变缓;当放电电压增加到一定值时,电流热效应使被加工板料的温升足够大,其应力应变曲线发生显著改变,胀形高度随温度变化关系由原来的单调下降转变为单调上升。在能量相同的情况下,当集肤深度超过板厚时,在一定温度范围内,厚度小的板料胀形高度小于厚度大的板料的胀形高度。 相似文献
8.
粘性介质压力成形(ViscousPressureForming,VPF)是一种适合于难变形材料板金零件制造的软模成形工艺。采用粘性介质胀形实验研究了反向压力对5A02铝合金板料成形性能的影响,结果表明在一定范围内的反向压力有利于抑制板料的平面各向异性,而在更高的反向压力条件下板料具有更好的成形性。 相似文献
9.
10.
粘性介质反向压力胀形对5A02铝合金板成形性的影响 总被引:1,自引:0,他引:1
粘性介质压力成形(Viscous Pressure Forming,VPF)是一种适合于难变形材料板金零件制造的软模成形工艺。采用粘性介质胀形实验研究了反向压力对5A02铝合金板料成形性能的影响,结果表明在一定范围内的反向压力有利于抑制板料的平面各向异性,而在更高的反向压力条件下板料具有更好的成形性。 相似文献
11.
Deng-Kui Zhang Guo-Qing Wang Ai-Ping Wu Ji-Guo Shan Yue Zhao Tian-Yi Zhao Dan-Yang Meng Jian-Ling Song Zhong-Ping Zhang 《金属学报(英文版)》2019,32(6):684-694
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone. 相似文献
12.
After nearly two years'tense construction the first phase of industrialized base of Shenyang Research Institute of Foundry 《中国铸造》2008,5(1):63-64
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation. 相似文献
13.
目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。 相似文献
14.
The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C). 相似文献
15.
Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems. 相似文献
16.
The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel. 相似文献
17.
Tang Dynasty 《中国铸造》2014,(4):I0002-I0003
<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also 相似文献
18.
《中国铸造》2014,(5):464-466
The 9th China International Diecasting Congress & Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition. 相似文献
19.
《机床与液压》2014,(12)
正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc- 相似文献
20.