Z. Chen
,
C.L.Chen
,
L.M. Hao
金属学报(英文版)
Numerical simulation based on phase field method
is performed to describe solidification process of pure material in
a free or forced flow. The evolution of the interface is showed, and
the effects of mesh grid and flow velocity on succinonitrite shape
are studied. These results indicate that crystal grows into an
equiaxial dendrite in a free flow and into an asymmetrical dendritic
in a forced flow. With increasing flow velocity, the
upstream dendritic arm tip grows faster and the downstream arm grows
slower. However, the evolution of the perpendicular tip has no
significant change. In addition, mesh grid has no influence on
dendritic growth shape when mesh grid is above 300x300.
关键词:
Phase field method
,
null
李开明
,
李亚洲
,
冯维贵
,
林长
量子电子学报
doi:10.3969/j.issn.1007-5461.2007.05.014
采用非线性反馈控制,用附加了带参数的正弦项对Chen系统进行了有效的控制.随着参数k的逐渐增大,系统的动力学行为呈现出一系列的变化.数值研究结果表明:随控制参数的增大,驱动信号的强度渐大,混沌系统由混沌运动到周期轨道,最终到一相点.
关键词:
混沌
,
Chen系统
,
不动点
,
Lyapunov指数
,
反馈控制
Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
王晓旭
,
陈利
材料工程
doi:10.3969/j.issn.1001-4381.2011.11.001
通过单根Z-pin从复合材料层合板中拔出的试验方法,测试了Z-pin的拔出强度,计算了Z-pin的临界埋入深度,并引入抗拉强度利用率概念来表征Z-pin的抗拉强度在拔出过程中的利用程度.结果表明,直径0.50mm和0.28mm的Z-pin临界埋入深度分别约为5.1mm和3.1mm.当Z-pin的埋入深度小于临界埋入深度时,Z-pin从层板中拔出；Z-pin拔出强度与埋入深度成正比,与Z-pin的直径成反比；当Z-pin的埋入深度大于临界埋入深度时,Z-pin发生断裂,Z-pin的抗拉强度利用率达到100％.最后提出了提高抗拉强度利用率的建议.
关键词:
Z-pin
,
拔出强度
,
复合材料
,
拔出试验
,
抗拉强度
王晓旭
,
陈利
航空材料学报
doi:10.3969/j.issn.1005-5053.2011.4.017
通过三种复合材料Z-pin的轴向压缩试验,观察了各Z-pin的压缩行为,分析了三种复合材料Z-pin在不同长度时的极限应力及其失效形式.结果表明,直径为0.50mm的碳纤维Z-pin的压缩性能最好,其各长度Z-pin所能承担的极限应力都较大.直径0.28mm的碳纤维Z-pin易发生失稳现象,芳纶纤维Z-pin在压缩力的作用下,接触端容易受到破坏.两种碳纤维Z-pin临界应力的理论值与试验值吻合较好,但芳纶纤维Z-pin的临界应力的试验值比理论值偏低.
关键词:
Z-pin
,
复合材料
,
压缩试验
,
临界应力
Li XING
,
Jie ZHAO
,
Fuzhong SHEN
,
Wei FENG
材料科学技术（英文）
A Z-parameter method is used to evaluate the damage process of HK40 austenitic steel. By using Z-parameter based on the Larson-Miller method, the nonlinear master curve of the log stress vs Larson-Miller parameter P can be expressed as: P=27.74-3.4lgσ-0.032σ, and a family of curves parallel to the master curve can be written as: P=(27.74-Z)-3.4lgσ-0.032σ, where Z represents the magnitude of the deviation from the master curve. According to the creep rupture data both from different segments of a serviced tube and from the same segment locations with different service time, the value of parameter Z has close relationship with the deterioration of creep rupture properties. The damage state of the samples is evaluated by monitoring the changes in natural frequency f and Young0s modulus E, and the relationships between Z and the damage parameters are discussed.
关键词:
Damage evaluation
,
蠕变断裂
,
奥氏体钢
,
Z参数
詹勇军
,
王锋
,
白黎
,
张素银
,
唐永健
,
吴卫东
,
谌家军
材料导报
以材料非线性光学性质的测试为基础,介绍了原始Z扫描技术的基本原理与数据处理;重点论述了双色时间分辨Z扫描技术的理论,并分析了它在材料光学非线性效应测试中展现的优越性以及应该注意的关键问题.根据Z扫描技术理论和实验的最新研究成果,总结了Z扫描技术的两条发展思路,即:CCD相机代替能量或功率计进行信号的采集和多种改进方法应用于实验测试.
关键词:
Z扫描技术
,
非线性光学效应
,
双色时间分辨Z扫描技术
,
CCD相机
李伟东
,
刘刚
,
安学锋
,
益小苏
复合材料学报
研究了层间“离位”附载多孔薄膜结构形式增韧层的大厚度纤维预成型体中等代流体(树脂)沿预成型体厚度方向(z向)的流动行为,通过压力传感器监测z向流动RTM(z-RTM)工艺注射过程中进、出胶口压力的变化规律,进一步反推树脂在层间“离位”增韧与非增韧预成型体中的宏观流动及微观浸润模式.结果表明,在z-RTM工艺注射过程中,树脂在沿纤维束间z向快速流动的同时完成对纤维丝束内部的浸润.层间“离位”附载的增韧层虽延缓了树脂的宏观流动,但使流动前锋曲面更加平滑.层间“离位”增韧预成型体z向渗透率为3.5×10-15m2,与非增韧预成型体的z向渗透率2.9×10-14m2相比,降低约一个数量级.
关键词:
z向流动
,
树脂传递模塑
,
预成型体
,
“离位”增韧
,
渗透率
