郎文昌肖金泉宫骏孙超黄荣芳闻立时
金属学报
doi:DOI:10.3724/SP.J.1037.2009.00556
研究了轴对称磁场对电弧离子镀弧斑运动的影响规律, 利用有限元分析软件FEMM对轴对称磁场的分布进行了模拟, 采用SHT-V型磁场测试仪测试了磁场强度, 分析了靶面不同磁场分量的分布规律. 从电弧斑点放电的物理机制出发, 探讨了不同磁场分量和轴对称磁场对电弧离子镀弧斑运动的影响机制. 结果表明, 轴对称磁场通过影响空间正电荷密度n+的分布而作用于弧斑运动; 随着轴对称磁场横向分量的增加, 电弧斑点由随机运动逐渐转变为向靶面边缘扩展的旋转运动, 弧斑运动速度加快, 电弧电压升高, 电流下降; 当横向分量增加到临界强度(BT≈30 Gs)时,弧斑在靶材边缘稳定的快速旋转运动并在靶沿处上下抖动, 弧斑分裂, 靶面中心处每隔0.5 s左右出现多个细的圆斑线, 然后很快向外扩展消失; 靶材边缘出现明显的刻蚀轨道.
关键词:
电弧离子镀
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axisymmetric magnetic field
,
finite element analysis
,
cathode spot movement
崔航陈怀宁陈静黄春玲吴昌忠
材料研究学报
采用球形压头的数值模拟表明, 当应变硬化指数n大于0.23时, 不论屈服应变σy/E为何值, 在压入过程中所有材料的压痕周围均出现凹陷; 当n小于0.23时, 随着σy/E的增大, 材料由凸起向凹陷转变; 当σy/E大于0.02时, 不论n为何值材料也都出现凹陷; 当σy/E小于0.02时, 材料出现凸起向凹陷的转变. 当比值残余压痕深度/最大压入深度(hf /hmax)小于0.76时, 材料出现凹陷, n值越大凹陷越严重; 当(hf /hmax)}>0.76, 若n<0.23材料出现由凸起向凹陷转变, 若n>0.23材料均发生凹陷. 还得到了反映凸起凹陷的表观参量c2与接触面积Am之间的函数关系, 分析了c2对压痕硬度误差的影响规律.
关键词:
材料科学基础学科
,
finite element analysis
,
pile-up and sinking-in
,
spherical indentation
,
yield strain
,
strain hardening exponent
刘旭东
,
曹小明
,
张洪延
,
张劲松
材料研究学报
用有限元方法分析了三维连通网络碳化硅的电特性, 计算了电阻值.
结果表明, 计算值与测量值吻合得很好.
电压的加载位置对碳化硅三维连通网络的电流分布有较大的影响.
两端均匀加载电压有利于产生比较均匀的电流分布.
由金刚石点阵结构单胞所组成的网 络具有空间三维连通的特点,
而简单长方体单胞所组成的网络只具有一维连通的结构特征,
在$L/S\gg$1 cm$^{-1}$的情况下,
金刚石点阵结构型泡沫陶瓷内电流的分布仍具有三维连通特征.
关键词:
无机非金属材料
,
three-dimensional networks
,
finite element analysis
YU Hui
,
DU Feng-shan
,
XU Zhi-qiang
钢铁研究学报(英文版)
Roller pass is one of the key factors affecting the product quality in the retained mandrel rolling process. The metal flow condition of rolling deformation area was researched using the FEA (finite element analysis) software Marc. The influences of the pass bottom radius, the sidewall radius, the sidewall angle, the roller shoulder fillet radius, as well as the roller gap on the rolling process under the conditions of different friction were discussed. Based on these results, the changes of the workpiece exit width, the mandrel axial force, the rolling force, and the rolling torque associated with various parameters were determined, which would provide the basis for designing the pass and determining the rolling condition reasonably.
关键词:
finite element analysis
J. Li
,
W. Liu
,
Y.Q. Lai
,
null
,
null
金属学报(英文版)
Two full 3D steady mathematical models are developed by finite element method (FEM) to calculate coupled physics fields: the electro-magnetic model is built and solved first and so is the fluid motion model with the acquired electromagnetic force as source body forces in Navier-Stokes equations. Effects caused by the ferromagnetic shell, busbar system around, and open boundary problem as well as inside induced current were considered in terms of the magnetic field. Furthermore, a new modeling method is found to set up solid models and then mesh them entirely with so-called structuralized grids, namely hex-mesh. Examples of 75kA prebaked cell with two kinds of busbar arrangements are presented. Results agree with those disclosed in the literature and confirm that the coupled simulation is valid. It is also concluded that the usage of these models facilitates the consistent analysis of the electric field to magnetic field and then flow motion to the greater extent, local distributions of current density and magnetic flux density are very much dependent on the cell structure, the steel shell is a shield to reduce the magnetic field and flow pattern is two dimensional in the main body of the metal pad.
关键词:
coupled simulation
,
null
,
null
,
null
,
null
