基于ANSYS的铸嘴流体耦合场三维有限元仿真分析

作者用大型有限元分析软件ANSYS对铸嘴内稳态层流铝熔体进行仿真分析。实现了三维建模。解决了三维热一流耦合求解的问题，得到铝流体的速度、压力及温度的分布图。分析了铸嘴出口速度和温度的分布规律及其对连续铸轧的影响。     

Hybrid numerical scheme for time-evolving wave fields

Many problems in geophysics, acoustics, elasticity theory, cancer treatment, food process control and electrodynamics involve study of wave field synthesis (WFS) in some form or another. In the present work, modelling of wave propagation phenomena is studied as a static problem, using finite element method and treating time as an additional spatial dimension. In particular, WFS problems are analysed using discrete methods. It is shown that a fully finite element-based scheme is very natural and effective method for the solution of such problems. Distributed WFS in the context of two-dimensional problems is outlined and incorporation of any geometric or material non-linearities is shown to be straightforward. This has significant implications for problems in geophysics or biological media, where material inhomogeneities are quite prevalent. Numerical results are presented for several problems referring to media with material inhomogeneities and predefined absorption profiles. The method can be extended to three-dimensional problems involving anisotropic media properties in a relatively straightforward manner. Copyright © 2006 John Wiley & Sons, Ltd.     

考虑次内力的桁架结构有限元分析

用有限元软件ANSYS对带式输送机栈桥的桁架结构进行了计算，结合实例着重探讨了考虑次内力时的桁架结构有限元分析在建模过程中需要解决的问题。     

利用Love波特性计算地基动力响应

本文利用Love波弥散特性在频域上对地基出平面振动及扭振问题进行了研究。在计算区域内结构将采用有限单元划分,而在边界上则根据Love 面波特性使用传递边界有限单元。本文同时讨论了不同模态波对结构动力响应的贡献。本文方法也适合于静力分析。     

Lyapunov analysis of the approximate motion equations of flexible structures

In this paper, the effectiveness of the approximate motion equations of a flexible structure, obtained by the RitzKantorovich method, is analysed by using Lyapunov functions. The analysis, which is restricted to the case of a single flexible beam for the sake of simplicity, is carried out under the assumption that a partial dissipation is present, affecting only the first degrees of freedom of the system. By means of suitable Lyapunov functions, an overbounding estimate of the quadratic approximation error is determined as a decreasing function of the approximation order. The analysis is completed by considering the two ‘extreme’ cases: the theoretical absence of dissipation and the presence of structural dissipation, affecting all the infinite degrees of freedom.     

非线性地基上桩结构物空间分析

本文提出了桩结构物－非线性地基空间相互作用分析的迭代法和非线性有限元法。其中，桩基分析用ｐ－ｙ曲线法。结合实际结构物进行了大量的计算及比较分析，成果是令人满意的，可以付诸应用。     

Computational study of transport processes in a single-screw extruder for non-newtonian chemically reactive materials

A numerical study of the transport phenomena arising in a single-screw extruder channel is carried out. A non-Newtonian fluid is considered, using a power law model for the variable viscosity. Chemical reaction kinetics are also included. Finite difference computations are carried out to solve the governing set of partial differential equations for the velocity, temperature and species concentration fields, over a wide range of governing parameters for the case of a tapered screw channel. The numerical treatment for this combined heat and mass transfer problem is outlined. A marching procedure in the down-channel direction is adopted and the validity of the scheme for practical problems discussed. For large viscous dissipation, the material heats up considerably due to the prevailing shear field, affecting the viscosity significantly, and results in large changes in the pressure development at the end of the channel. The rate of reaction controls the mass diffusion rate which in turn affects viscosity and the flow significantly. The dimensionless throughput,q _v , is one of the most important parameters in the numerical solution. The dimensionless pressure variation is very sensitive toq _v , and orders of magnitude changes are possible for small variations inq _v . Schemes for dealing with other important effects such as back flow, heat transfer by conduction in the barrel, and the effect of the die are also outlined. A list of symbols is given at the end of the paper This is publication No. F-10544-4-91 of the New Jersey Agricultural Experiment Station supported by State Funds and the Center for Advanced Food Technology (CAFT). The Center for Advanced Food Technology is a New Jersey Commission on Science and Technology Center. This work was also supported in part by the US Army Research Office.     

Effect of plasticity on the residual stress measurement using the groove method

The mechanical methods based on milling rectilinear or annular grooves on a component's surface and measurement of relaxed strains are some of the most used semi-destructive methods for the determination of residual stresses. These are evaluated from the relaxed strains by means of equations based upon the linear elastic theory. In this paper the errors due to yielding localised at the bottom of the groove have been investigated. The analyses were carried out by means of the finite element technique varying the most important parameters involved. The experimental results show a good agreement with the numerical ones.     

Intelligent Control of Consolidation and Solidification Processes

Intelligent processing of materials (IPM) deals with the integration of process models and in situ sensors into an intelligent process controller to achieve desired material properties. IPM-based control systems recently have been developed for both consolidation and solidification processes. This article explores the application of models based on the finite- element method (FEM) to develop process actuation systems, to design process schedules and component shape, and to develop a control model with which to control the process. The results in this article were presented at the AeroMat ’93 Advanced Aerospace Materials/Processes Conference and Exposition, Anaheim, CA, 7–10 June 1993     

PDC钻头在胜利油田深井钻井中的应用

胜利油田为提高深井钻井速度，试验应用了PDC钻头，结果表明，深井钻井应用PDC钻头可大幅度提高机械钻速，缩短建井周期，降低钻井成本，经济效益明显。通过大量的现场试验，扩大了PDC钻头在胜利油田的使用范围，并取得很好的效果，初步形成了PDC钻头推广应用区域模式。详细介绍了胜利油田不适用PDC钻头钻进的地层岩性，给出了钻头选型及钻井参数选择原则，并对应用效果进行了分析。