查询词典 AND element

In this dissertation the"Penalty"finite element method was employed to compute the velocity of the three-dimensional flow of power-law fluid in a profile die. In order to decrease the needed computer memory and raise the stability of numerical simulation, a set of decoupled methods such as PFEM, pseudo-body force method and transformation of momentum equation to the elliptic equation was developed to establish the general finite element equations to compute the distributions of velocity and viscoelastic stress of the three-dimensional viscoelastic flow of the Phan ThienTanner fluid in a profile die. During numerical simulation of the extrudate swell of the PTT fluid, the flow in the die and out of the die was analyzed separately, which demands less computer memory.

本文建立了求解挤出口模内幂律流体流动速度场的通用三维罚有限元模型；对于非线性粘弹性的Phan Thien-Tanner流体，为了降低模拟计算对计算机硬件的要求，并使模拟计算更加稳定，采用了一种去耦算法，包括罚有限元方法、拟体力方法和动量方程的椭圆类方程转化方法，并建立了求解速度场和粘弹性应力场的总体有限元方程；对于PTT流体的挤出胀大问题，提出了挤出胀大熔体口模内外分离模拟法，这样可以显著降低数值模拟对计算机硬件的要求。

In this dissertation the"Penalty"finite element method was employed to compute the velocity of the three-dimensional flow of power-law fluid in a profile die. In order to decrease the needed computer memory and raise the stability of numerical simulation, a set of decoupled methods such as PFEM, pseudo-body force method and transformation of momentum equation to the elliptic equation was developed to establish the general finite element equations to compute the distributions of velocity and viscoelastic stress of the three-dimensional viscoelastic flow of the Phan ThienTanner fluid in a profile die. During numerical simulation of the extrudate swell of the PTT fluid, the flow in the die and out of the die was analyzed separately, which demands less computer memory. The key techniques used in numerical simulation of the three-dimensional extrusion from dies such as decision of boundary conditions, creation of initial velocity field, selection of penalty factor, high Weissenberg number problem , regeneration of the free surface were studied in detail.

中文题名聚合物异型材口模挤出三维流动研究副题名外文题名 Study on three-dimensional flow of polymer melts during the process of profile extrusion from dies 论文作者涂志刚导师柳和生包忠诩教授学科专业材料加工工程研究领域\研究方向学位级别博士学位授予单位南昌大学学位授予日期2001 论文页码总数148页关键词挤出成型聚合物材料挤出口模聚合物异型材馆藏号BSLW /2003 /TQ320 /9 本文建立了求解挤出口模内幂律流体流动速度场的通用三维罚有限元模型；对于非线性粘弹性的Phan Thien-Tanner流体，为了降低模拟计算对计算机硬件的要求，并使模拟计算更加稳定，采用了一种去耦算法，包括罚有限元方法、拟体力方法和动量方程的椭圆类方程转化方法，并建立了求解速度场和粘弹性应力场的总体有限元方程；对于PTT流体的挤出胀大问题，提出了挤出胀大熔体口模内外分离模拟法，这样可以显著降低数值模拟对计算机硬件的要求。

The drawing and extruding problems are analyzed and calculated by means of the theory and finite element program in this paper. It has been proved that the theory of large strain elastic-plastic finite element and elastic-plastic hydrodynamic lubrication has a wide practice value.

应用本文的理论和有限元程序，分析和计算了拉拔和挤压实例，证实了有限变形弹塑性有限元法和弹塑性流体动力润滑理论在金属塑性成形领域中具有广泛的实用价值。

The invention discloses a device for spreading machine docking with trucks, which consists of damping mechanisms installed on both side between the spreading machine and the roller; the damping mechanism consists of side plate 1, sliding block 2, flexible element 3, and shaft 4, the flexible element 3 is sleeved on the shaft 4 of which one end linked with spreading machine and the other with sliding block 2, side plate is on upper section of sliding block 2 and fixed on the machine, lower section of sliding block is linked with roller.

本发明公开了一种摊铺机与卡车对接缓冲装置，它为设置于摊铺机机身前端与推滚之间的左、右各一副阻尼机构(10)；所述阻尼机构(10)包括端板(1)、滑块(2)、弹性元件(3)和轴(4)，弹性元件(3)套于轴(4)上，轴(4)的一端与推铺机机身(5)相连，滑块(2)与轴(4)的另一端相连，端板(1)位于滑块(2)上段之外，并固定于推铺机机身(5)上，滑块(2)的下段与推滚(6)相接。

In the cylindrical coordinates, the related basic formula and solve method of the equivalent boundary element method were established and derived, and a new contact element was introduced to model the hybrid of structure and soil.

同时建立并推导了在柱体坐标系下插入式大圆柱壳墩式结构的等效边界元数值分析的相关基本方程和求解方法，并提出了一种新的接触面单元以模拟结构和土体间不同材料的耦合关系。

Trace element exhibits enrichment of LREE and antipathic elements. Trace element spidergram of obvious right deviation and extremely high containing of Sr, Zr and Hf are different from the negative anomaly of dunite which lies the bottom of ophiolite, but has weak positive anomaly.

微量元素显示LREE和不相容元素的富集，右倾的微量元素分布模式，异常高的Sr含量，Zr、Hf不同于蛇绿岩底部纯橄榄岩的负异常，而显示出微弱正异常，这些特征都与经典蛇绿岩层序底部的地幔橄榄岩不同。

Complex--valued kernel structure element frequency filtering morphological centroid scale--space image parallel processing system has been proposed and established, in which the complex--valued kernel structure element frequency filtering CGH was designed and made by the way of Burckhardt which could improve recording accuracy and reduce quantity noise.

提出并构造了复值核结构元频域滤波形态学矩心尺度--空间图象处理系统，其中采用编码精度高和量化噪声小的Burckhardt方法设计和制作了复值核结构元频域滤波器CGH模板，并对系统处理图象的面积、系统对CGH复位精度的要求进行了分析。

However,authors still do not find the relevant references on convergence and symmetric problems of the semi-analytical solution.Based on the semi-analytical solution for Hamilton canonical equation theory,the formulations of the clamp and simply supported and symmetric boundary conditions on the Hamiltonian element are derived by the variational principle.Several numerical examples show that with increase of meshes,the convergence rate of the semi-analytical solution is faster than the convergent rate of traditional finite element method based on displacement.

①在厚度上没有任何位移和应力模式的假设，由于传递矩阵方法的引入，从理论上讲，不受板壳厚度或层合板壳层数的限制；②采用弹性力学的Hamilton正则方程半解析法，可以克服边界的局部化效应[8]；③由于在平面内或圆柱壳的曲面内采用了有限元法，所以一般的板壳问题不受结构侧面边界条件的限制，在复杂工程板壳问题上具有广泛的应用领域。

It is usually that the solution for the Dirichlet problem can not be obtained actually. With the development of computers, people pay more and more attention to the numerical solution. Many ideas and methods have appeared. Among them the finite element method has become most popular. But the finite element method has some weaknesses and limitations too. First, it is not fit to higher-dimensional problems.

绝大多数Dirichlet问题的解析解往往难以得到，随着计算机技术的发展，Dirichlet问题的数值解法越来越受到人们的重视，新的思想和方法不断涌现，其中有限元法已经发展成为目前求解Dirichlet问题的最主要的数值方法，但是有限元法解决该问题时，存在着一些弱点和局限。

It is usually that the solution for the Dirichlet problem can not be obtained actually. With the development of computers, people pay more and more attention to the numerical solution. Many ideas and methods have appeared. Among them the finite element method has become most popular. But the finite element method has some weaknesses and limitations too.

绝大多数Dirichlet问题的解析解往往难以得到，随着计算机技术的发展，Dirichlet问题的数值解法越来越受到人们的重视，新的思想和方法不断涌现，其中有限元法已经发展成为目前求解Dirichlet问题的最主要的数值方法，但是有限元法解决该问题时，存在着一些弱点和局限。

Molecular Distillation is a kind of high vacuum distillation method, which is suitable for the separation of high boiling, heat sensitivity and viscidity products.

分子蒸馏技术是一种在高真空条件下进行的连续蒸馏过程，适合于分离高沸点、热敏性及具有生物活性的混合物。

They are to the Noughties what yuppies were to the Eighties .

那在六十年代是时髦的，但在八十年代肯定是过时了