厚轴对称边界层数值计算的压力积分法

采用H—S法决定边界层外边界上的压力分布,边界层对势流的粘性干扰采用附加回转体排挤厚度来处理。用量阶比较法导出高阶厚轴对称边界层方程,静压的法向变化没有引用线性假设,而是用积分法求解而得到。在尾端区用“半流线”坐标以代替通常的壁面坐标,可连续地从边界层区计算到尾流区。本文还分别探讨了纵向曲率、静压梯度和法向速度的影响,得到了具体的数量结果,这对于研究厚边界层理论有一定的参考价值。     

基于PVDF的三维机器人触觉传感器有限元分析

为了解决压电层合板层间应力连续性问题,从而更为准确地预测传感器的实际输出,利用COMSOL Multiphysics对基于PVDF压电薄膜的三维机器人触觉传感器进行有限元建模。利用三维线性理论建立了压电层半解析轴对称有限元模型,得出分别沿三个方向施加单向力时触觉传感器各压电薄膜的电压响应。仿真结果与标定值之间的误差小于6%,验证了设计的合理性和可行性。     

固体冲击模拟的轴对称光滑粒子法

为提高光滑粒子（Smoothed Particle Hydrodynamics,SPH）法模拟轴对称固体冲击的计算效率,将三维模型简化到二维轴对称平面上;为避免在构造轴对称SPH法过程中对光滑函数进行环向积分,在传统SPH法的基础上通过直接离散的方式,利用导数关系式与SPH法的近似特性,构造在轴对称柱坐标系下具有对称形式的粒子近似方程组．以泰勒杆冲击为例,将该方法的计算结果与实验以及商业软件得到的结果进行对比分析,验证所构造的轴对称SPH法的可靠性和正确性．     

Topology/shape optimisation of axisymmetric continuum structures – a metamorphic development approach

A novel topology/shape optimisation method for axisymmetric elastic solids, based on solid modeling and FE analysis, is presented. Optimal profiles of minimum-mass axisymmetric structures are sought by growing and degenerating simple initial structures subject to response constraints. The rates of the growth and degeneration are controlled based on the current objective and constraint functions of the optimisation problem under consideration. The optimal structures are developed metamorphically in specified infinite design domains using both quadrilateral and triangular axisymmetric finite elements that are ideally suited for modeling continua involving curved boundaries.The robustness of this fully automatic method is studied and validated with the first example of seeking the optimal shape of a centrally suspended axisymmetric object with minimum strain energy caused by self-weight. Then the method is applied to a practical industrial design problem: the design of a turbine disk. The variations of load and boundary conditions caused by shape change in these problems, including the gravitational and centrifugal loads, and temperature distribution are accommodated in the optimisation procedures. Thus, the design model closely resembles the real design problem. The results demonstrate the success of the method in generating optimal but realistic solutions to practical design problems.     

轴对称矢量喷管数值模拟及数学模型研究

应用数值模拟方法对轴对称推力矢量喷管的内流场性能进行了研究，采用Jameson提出的有限体积法计算了矢量喷管的内部流场和性能参数，分析了性能参数及其相关参数之间的关系，从而建立了轴对称推力矢量喷管的数学模型。     

NUMERICAL STUDY OF FLOW PAST AN AXISYMMETRIC BODY WITH A RING WING AT VARIOUS ATTACK ANGLES

1 .　INTRODUCTIONFortraditionalbody fittedgridsystemusedtocomputetheflow pasttheaxisymmetricbody ,thesingularityonthelongitudinalaxisisalongstand ingobstacle .Rationalsolutionishardtobeachievedevenwithfinemeshesgeneratedwithinthevicinityofthelongitudinalaxis .Hence ,appro priategridsystemisreguiredtoavoidthesingulari ty .Extensivenumericalexperimentsareconductedtoobtainthedesired gridsysteminthis paper .BasedontheideaofDDM[1] ,theoriginalflowfieldofthebodyisdividedinto 8sub domainsac cor…     

轴对称拉伸流动中大表面张力下球形液滴Stokes流动的准确解

本文采用轴对称情形下内外Stokes流动的Sampson级数解求出了轴对称拉伸流动中大表面张力下球形液滴stokes流动的准确解。该准确解表达式简单且为有限形式。文中详细分析了流线谱,粘度比对内外流的影响以及内流的速度分布和压力分布。     

基于四边形面积坐标的广义协调轴对称单元

利用了点组合广义协调和周广义协调条件,基于四边形面积坐标方法构造了含内参的4结点四边形空间轴对称单元AQACQ6。通过进一步对内参应变矩阵进行合理修正,从而形成新单元AQACQ6M,该单元能够通过强式分片检验。两种单元的位移场都达到对整体坐标的二次完备。数值算例表明:上述轴对称单元不仅精度高,而且抗网格畸变和几乎不可压缩问题能力优于等参单元,显示了面积坐标和广义协调理论的优越性。     

A perturbation-based numerical method for solving a three-dimensional axisymmetric indentation problem

The three-dimensional axisymmetric problem of the indentation of a thin compressible linear elastic layer bonded to a rigid foundation is considered. Approximate analytical solutions of the problem that incorporate a large portion of the singular deformation gradients near the edge of the indenter are presented. An accurate closed-form expression for the deformation as well as the deformation gradient throughout the layer is provided and its effectiveness in solving the problem numerically is demonstrated. By incorporating the approximate solution into the numerical scheme the accuracy and convergence rate increase dramatically.     

Four‐node incompatible plane and axisymmetric elements with quadratic completeness in the physical space

In this paper, four‐node incompatible elements with quadratic completeness in the physical space are developed for plane and axisymmetric problems. Various revision techniques of the incompatible strain matrix or shape function are proposed to guarantee the incompatible elements to pass the constant stress patch test. In contrast with other elements in the same level, the present one gives reasonable stress solutions without any stress recovery such as the bilinear extrapolation and least square approximation. Numerical examples are given to investigate the accuracy, sensitivity to mesh distortion and locking in the incompressible calculation of the present method when irregular coarse meshes are used. Copyright © 2004 John Wiley & Sons, Ltd.