Sobolev方程各向异性非协调混合元的超逼近分析

研究Sobolev方程的非协调Galerkin混合有限元方法.对Sobolev方程进行了Galerkin逼近,并且利用单元的特殊性质在不需要Ritz投影情况下得到了超逼近性,最后利用插值后处理给出了一类新的混合元格式的收敛性分析和超逼近结果.     

变系数黏弹性方程各向异性Q_1元逼近

在各向异性网格上分析了具有变系数的黏弹性方程双线性有限元解的收敛性,利用新的技巧和方法导出了超逼近及超收敛结果。     

非线性Klein-Gordon方程各向异性高精度有限元分析

讨论了在半离散格式下的各向异性双线性元对非线性Klein-Gordon方程的逼近。利用单元自身的特殊性质和一些新的分析技巧得到了超逼近性质,通过构造一个插值后处理算子导出了整体超收敛结果。     

非线性Klein—Gordon方程各向异性高精度有限元分析

讨论了在半离散格式下的各向异性双线性元对非线性Klein—Gordon方程的逼近。利用单元自身的特殊性质和一些新的分析技巧得到了超逼近性质,通过构造一个插值后处理算子导出了整体超收敛结果。     

抛物问题非协调旋转Q1元的超逼近性分析

在正方形网格上讨论了非协调旋转Q1元对二阶抛物方程的逼近.利用该单元的特殊性质及新技巧,导出了其超逼近性质.     

各向异性网格上Shroedinger方程全离散格式的非协调元逼近

研究了在各向异性网格下Shroedinger方程的Crank-Nicolson-Galerkin全离散格式的一个非协调有限元逼近,并利用该格式的特殊构造得到了能量模的逼近性质。     

三维ACM元各向异性特征判定

为了摆脱传统有限元对网格正则性条件的依赖,近年来发展了各向异性有限元。在各向异性元的收敛性及误差分析中,各向异性特征的验证是一个核心技术。本文把传统的各向异性特征判定方法推广到三维的ACM元上,验证了三维ACM元的各向异性特征,为进一步研究该单元的各向异性收敛性、误差估计、后验误差估计及数值分析提供了理论依据。     

抛物积分微分方程的旋转Q1元的超逼近分析

主要讨论在正方形网格上抛物积分微分方程的旋转Q1非协调元的超逼近性,在不需要Ritz-Voherra投影及任何修正格式情况下．利用该单元的特殊性质,得到了相应的超逼近结果．     

Taylor公式在高精度算法中的应用

讨论Taylor公式在外推算法以及积分恒等式中的应用 ,说明Taylor公式在高精度近似计算中的重要作用     

非线性湿气迁移方程的EQ1rot非协调元的超收敛分析

在半离散格式下研究了非线性湿气迁移方程的EQ1rot非协调有限元逼近问题.利用该有限元的相容误差在能量模意义下可以达到O(h2)比其插值误差高一阶的特殊性质,再结合高精度分析和平均值技巧导出了O(h2)阶的超逼近性,进而运用插值后处理技术得到了超收敛结果.     

一类抛物问题的有限元高精度单步格式

首先给出了形如 ( 1)的抛物问题的半离散有限元所满足的常微分方程组 ,然后在时间变量上剖分后得到了这类抛物问题的空间和时间变量都有 4阶精度的有限元高精度单步格式 ,并给出了证明     

高陡岩土边坡有限元分析

本文以高陡岩土边坡实测资料为研究对象,遵循资料收集—现场调研—模型建立—程序设计—工程分析的研究思路,采用有限元强度折减数值分析方法,通过前后处理软件,综合考虑土性参数和边坡边界条件的变化,从计算结果中分析边坡的位移,变形及其塑性发展趋势和安全系数。     

清镇职教城岩质高边坡稳定性的有限元分析

为了掌握岩质高边坡开挖过程中的位移变形,应力应变规律,本文采用赤平极射投影法(Stereographic projection)与MIDAS/GTS有限元分析相结合的简化物理模型,对清镇职教城岩质高边坡的稳定性进行分析和判断.根据数值分析结果诊断岩质高边坡开挖后的地质缺陷部位,采用有限元分析和极限平衡法去优化边坡设计、评价支护后边坡稳定性.     

Arc-length technique for nonlinear finite element analysis

INTRODUCTION Complete investigation of the nonlinear be-havior of structures must follow the equilibriumpath; identify and compute the singular points likelimit or bifurcation points, whose secondary bran-ches in the equilibrium path must be examined andfollowed. Several techniques to achieve the solu-tion pattern on the equilibrium path were presentedin literature. Load controlled Newton-Raphson me-thod was the earliest method in this regard; but itfails near the limit point. To overcom…     

Arc-length technique for nonlinear finite element analysis

Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle, Received wide acceptance in finite element analysis, and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades, with particular emphasis on nonlinear finite element analysis of reinforced concrete structures.     

An adaptive finite element procedure for crack propagation analysis

INTRODUCTION The finite element method (FEM) has proved to be very well suited for the study of fracture mechanics. Nevertheless, modelling the propagation of a crack through a finite element mesh turns out to be difficult because of the modification of the mesh topology. Use of crack propagation laws based on stress inten-sity factor range is the most successful engineering application of fracture mechanics. The stress intensity factors are a very important parameter in fracture analys…     

汽车差速器壳的三维造型及有限元分析

差速器壳设计是汽车设计环节的关键,尤其差速器壳的强度分析是设计的重点之一。本文通过运用PROE软件进行三维设计,运用ANSYS软件对差速器壳进行强度分析,通过对差速器壳模型进行网格划分、差速器壳负载及边界条件的设定,计算求解得出差速器壳应力分布图,从而找出差速器壳易破坏部位,寻找到提高差速器壳强度的措施。     

玻化微珠保温砂浆外保温系统有限元分析

为研究玻化微珠保温砂浆外墙外保温系统在夏季和冬季环境下的温度和应力,基于热分析理论并利用ANSYS有限元软件对保温墙体进行了模拟分析。结果表明:玻化微珠保温砂浆具有优良的保温隔热性能,无论是夏季高温还是冬季低温,均能使室内温度保持稳定,其温度浮动在2℃以内;由于冬季室内外温差大,在冬季环境温度作用下,保温系统外表面温度应力比夏季环境下增大了83%;沿墙体厚度方向的应力分布,抗裂砂浆层应力最大,保温层应力最小。     

An improved axisymmetric wilson nonconforming finite element method for stress analysis

The Wilson and Taylor elements Q6 and QM6, the representative nonconforming finite element method (FEM), have been successfully developed and implemented in the finite element code SAP for improved displacement and stress analysis. This paper formulates an improved convergent nonconforming axisymmetric element AQM6 over the corresponding axisymmetric Q6 and QM6 elements. The proposed modified nonconforming axisymmetric element AQM6 satisfies the engineering patch test condition for convergence, and also meets the condition for suppression of spurious shear stress by using a special remedying procedure. The numerical test results are in agreement with the element performance. Project supported by CAO Guangbiao High-Tech F. of Zhejiang Univ. (No. U19902), Zhejiang Edu. Committee SRF for Outstanding Returned Overseas Scholars (No. G59990), US NSF (No. DDM-9313204) and Seiko Epson-Rutgers Univ. Project (No. 4-27365).     

Three-dimensional elasto-plastic finite element analysis of a soil-pile-bridge interaction

The soil-pile-bridge interaction of super-large pile groups is a very complex issue for the design of deep pile group foundations. In this paper, the load distribution on the pile top of a super large bridge foundation and its influential factors are analyzed comprehensively using a three-dimensional elasto-plastic finite element method. The adopted model and its input parameters are firstly verified by comparing the numerical results with the measured data of static loading tests of a single pile. Numerical analysis is then performed to investigate the load distribution and the load-settlement characteristics of super-large pile groups, and the models are verified using centrifuge laboratory model testing data. The mechanism of the interaction between pile groups and soil under different conditions is explored.