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91.
The kinetics of recrystallization for twin-roll casting AZ31 magnesium alloy with different thicknesses during homogenization was analyzed.It is shown that fine grains are first formed at the boundaries of deformed bands in the twin-roll casting slab.The recrystallized grains with no strain are gradually substituted for the deformed microstructure of twin-roll casting AZ31 magnesium alloy.The incubation temperature and time for the recrystallization of a twin-roll casting AZ31 magnesium alloy strip with a thickness of 3 mm are lower and shorter than those of the 6-mm thick strip,respectively.The 3-mm thick twin-roll casting magnesium alloy has finer grains than the 6-mm thick strip.The activation energies of recrystallization for twin-roll casting AZ31 magnesium alloy slabs with the thickness of 3 and 6 mm are 88 and 69 kJ/mol,respectively.The kinetics curves of recrystallization for twin-roll casting AZ31 magnesium alloy were obtained. 相似文献
92.
为了利用通用有限元软件来对复杂的均匀化方程进行便捷求解,从而对具有周期性构造复合材料有效性能进行预测.根据文献[1]提出的热应力方法和边界力方法将均匀化方程转化为通用有限元可以进行计算的形式,通过ABAQUS用户子程序和脚本语言的编写,便捷的实现了均匀化方程的求解,得到了均匀化系数.通过均匀化方程的ABAQUS的便捷求解(包括热应力方法和边界力方法),计算了单向复合材料有效性能,并与细观力学方法进行比较,结果表明两种方法具有一致性和有效性. 相似文献
93.
料仓贮料压力计算是料仓结构设计中的重要一环,其计算方式分为深仓和浅仓两种。本文通过具体算例分析,对钢筋混凝土料仓和钢料仓在贮料压力计算中应注意的压力复核问题进行了总结,提出了较实用的解决办法。 相似文献
94.
Guo-jun Wang ) Bai-qing Xiong) Yong-an Zhang) Zhi-hui Li) Pei-yue Li) ) State Key Laboratory for Fabrication Processing of Nonferrous Metals General Research Institute for Nonferrous Metals Beijing China ) Northeast Light Alloy Co. Ltd. Harbin China 《北京科技大学学报(英文版)》2009,16(4):427-431
The microstructure of the as-cast 2D70 aluminum alloy and its evolution during homogenization were investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) analysis. The results indicate that the microstructure of the as-cast 2D70 aluminum alloy mainly consists of the dendritic network of aluminum solid solution and intermetallic compounds (Al2CuMg, Al2Cu, Al9FeNi, Cu2FeAl7... 相似文献
95.
南京院开发的小型NGF型系列连续重力充气搅拌式生料均化库,已成功用于多条2500—10000t/d水泥熟料生产线。文章介绍了该库的均化工作原主要由三部分完成:一是库顶多点下料生料分配器;二是内、外充气系统;三是库底卸料装置及充气计量仓系统。同时详细分析了该库的结构组成和结构特点;还作了其中的二个应用实例及其效果。运行结果表明,该库的装备技术安全可靠,造价合理寿命长,均化原理先进,运行电耗低,均化效果好,达到国内外同类产品的先进水平。 相似文献
96.
Seismic vulnerability assessment of reinforced concrete silo considering granular material‐structure interaction 下载免费PDF全文
Kunpeng Guo Changdong Zhou Lingkai Meng Xiaoyang Zhang 《The Structural Design of Tall and Special Buildings》2016,25(18):1011-1030
As a special shell structure, silos are used in storing a wide range of multitudinous granular materials. However, seldom have researchers assessed seismic vulnerability of the reinforced concrete (RC) silo. This paper aims at studying the seismic vulnerability assessment of a silo, which is located in Zhoushan, China. Prior to assessing the seismic vulnerability of the selected RC silo, the validation of the hypoplastic constitutive model, which is used to simulate granular materials, is studied. After discussing the validation of the hypoplastic theory, the numerical model considering granular material‐structure interaction is developed by means of the ABAQUS software. And the numerical simulation results are compared with the experimental data obtained from a shaking table test discussed in order to confirm the validation of the numerical model, which is used to study the seismic vulnerability of the RC silo. Then the seismic fragility assessment of the selected RC silo is performed using the incremental dynamic analysis. The analytical results showed that the hypoplastic theory can be used to simulate the stored materials in the silo considering the collapse property before entering plastic state of granular materials. For the design basic acceleration, the fragility curves of the selected RC silo showed that the probability of exceeding the no or light damage state was about 2.12%. For the maximum considered earthquake, the exceeding probability of no or slight and the moderate damage states was 17.63% and 1.31%, respectively. With respect of the severe and total damage state, the exceeding probabilities were almost zero. Therefore, the selected RC silo structure has enough safety stock to withstand strong earthquakes in the future. Finally, a general design procedure considering seismic fragility assessment was presented in order to provide references for other structure design. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
97.
圆柱状卫星侧表面温度场均匀化设计 总被引:1,自引:0,他引:1
温度场均匀化设计因有利于航天器的稳定高效运行而获得越来越多的重视。本文针对简化的圆柱状卫星,采用仿生优化方法对给定量的高导热材料进行优化分布,以均匀化卫星侧表面温度场。同时,本文还基于理论分析了温度场均匀化过程中卫星的导热热阻和辐射热阻的变化情况,讨论了太阳光入射角度对卫星侧表面温度场的影响。结果表明,仿生优化方法能有效均匀化温度场,但该优化结果对应的温度场的稳定性在一定程度上受太阳光入射角度影响;在温度场均匀化过程中,卫星导热热阻与辐射热阻呈下降趋势,这表明卫星侧表面的传热性能在这一过程中得到了提高。 相似文献
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