Weimin MAO
,
Dong LI
材料科学技术（英）
The image stress of straight screw dislocations parallel to the medium surface covered by thin heterogeneous films was analyzed and deduced, in order to calculate the image shear stress. The relationship between image stress and distance from the screw dislocation to the interface of pure aluminum and its oxide covering was calculated based on the analysis. It was shown quantitatively that a sign conversion of the image stress appears in the case of thin oxide covering, while dislocation would pile up near the interface because of the possible slips of the screw dislocations induced by the image stress, which might break down the very thin oxide covering. Further investigation on edge dislocations or other dislocation configurations need to be done.
关键词:
Dislocation
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null
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null
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null
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null
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null
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null
曹海建
,
俞科静
,
钱坤
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2015.02.004
利用有限元软件Workbench,建立了三维中空夹芯复合材料结构模型,进行拉伸性能研究.利用该模型,探讨了材料在1 mm拉伸位移栽荷作用下纤维、树脂和复合材料的应力、应变分布.结果表明:三维中空夹芯复合材料在拉伸载荷作用下,“X”形芯材交叉处应力最大,最容易发生拉伸破坏;上下面板应力最小,最不容易发生拉伸破坏;复合材料在承受拉伸载荷作用时,增强体纤维起主要承载作用,基体树脂起次要作用;当拉伸位移栽荷达到1 mm时,材料的破坏模式主要为树脂破裂.
关键词:
三维中空夹芯复合材料
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有限元软件Workbench
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拉伸性能
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应力
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应变
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破坏模式
王有欣
,
毛明旭
,
王英才
上海金属
分析了X70管线钢试样不平度对规定总伸长应力(Rt0.5)的影响.分别采用滞后环法、试样压平法和计算补偿法来消除试样不平带来的试验误差.试验结果表明,与其他两种方法相比,试样压平法是目前最有效的方法.
关键词:
Rt0.5
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管线钢
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不平度
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应力
Hongyuan FANG
,
Chenglei FAN
,
Jianguo YANG
,
Ming LI
,
Zhen LUO
,
Xianzhong HOU
材料科学技术（英）
A new type of compound conduit is designed and the finite element method (FEM) is applied to analyze the mechanical performance of a typical compound conduit. The results of the numerical simulation confirm that the distributions of the strain, stress and the flexure distortion of the conduit are reasonable under the working conditions, and the stress and strain are continuous at the interface of the crust and the pipe liner. The conduit can endure 7.4 times of the working load before break, which fits well with that of the experiment and means that the conduit has good ability to bear overload. The peak value of the flexure distortion of the conduit (6 m) is about 3 mm in the middle bottom of the pipeline, which also accords well with that of the experiment.
关键词:
Compound conduit
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null
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null
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Guoqing CHEN
,
Kaifeng ZHANG
,
Guofeng WANG
,
Y
,
ong YU
材料科学技术（英）
Numerical simulation of hot-press sintering of nano-sized ceramic powders was introduced by the commercial finite element code MSC.MARC. The powder plastic model and the thermo-mechanical coupled quadrilateral element were developed and adopted in the simulation. The mechanical and thermal properties of the nano-sized alumina based powders were determined. In addition, the experimental research and numerical simulation of the sintering process of different initial densities were carried out. The stress state in sintering of green compacts with different initial densities was analyzed by the densification theory. The reason for the density fluctuations of as-sintered ceramic bulks was found out.
关键词:
Sintering
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null
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null
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Hongbo DONG
,
Yonglin KANG
材料科学技术（英）
With a geometrical model of porous material, a 3D finite-element analysis on the rolling process of spring steel- 60Si2Mn in the semi-solid state is carried out using software MARC. In terms of flat and groove rolling conditions, stress field and strain field are studied. The simulation results show that the rigid-viscoplastic model can accurately describe the semi-solid metal rolling process. Semi-solid slurry has the characteristics of low flow stress and good fluidity. During groove rolling, distribution of stress and strain on the cross-section of deformation zone is more uniform than that during flat rolling. The results of simulation are in good agreement with the experiment data, and show that semi-solid material fits for groove rolling.
关键词:
Finite-element analysis
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null
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