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对流扩散问题的稳定混合有限元法(英文)
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作者 张杰华 韩明华 《河南科学》 2010年第4期387-390,共4页
给出了对流扩散问题的一个稳定混合有限元公式,并证明了此公式的解是存在且唯一的.
关键词 对流扩散方程 稳定混合有限元法
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基于流体有限元法与大涡模拟技术的建筑风场与风效应分析
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作者 周岱 刘光众 +2 位作者 马骏 韩兆龙 黄橙 《建筑科学与工程学报》 CAS 北大核心 2013年第2期1-8,129,共8页
把流线迎风Petrov-Galerkin(SUPG)稳定化方法和三步方法与动态亚格子模型相结合,建立了一种基于任意拉格朗日-欧拉描述、可用于结构周围风场特性和风压分布分析的动态亚格子大涡模拟方法,基于该方法并运用分区交替求解算法分析流固耦合... 把流线迎风Petrov-Galerkin(SUPG)稳定化方法和三步方法与动态亚格子模型相结合,建立了一种基于任意拉格朗日-欧拉描述、可用于结构周围风场特性和风压分布分析的动态亚格子大涡模拟方法,基于该方法并运用分区交替求解算法分析流固耦合相互作用问题。对流场的空间离散,采用速度和压力的同阶插值函数;对流场的时间离散,运用具有二阶精度的三步格式稳定化有限元方法。利用Newmark逐步积分方法计算结构域,运用弹簧近似法进行网格域网格更新。对结构风效应和结构周围三维风场绕流及其特性进行了数值模拟,归纳总结了结构风效应和三维风场绕流的一些规律。结果表明:就网壳算例而言,考虑流固耦合模型效应后可以得到更高的风压系数。 展开更多
关键词 风场 风效应 稳定有限元法 大涡模拟 流固耦合
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浅析边坡稳定性分析研究 被引量:6
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作者 仝小芳 徐银鸣 《山西建筑》 2006年第21期119-120,共2页
介绍了边坡稳定性分析的定性、定量评价方法以及非确定性模型评价方法,并对边坡稳定性有限元分析方法作了比较,对边坡稳定性研究发展具有一定的指导意义。
关键词 边坡稳定 评价方法 有限元法
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基于子模型的大型复合材料飞机结构屈曲稳定性数值分析及优化技术研究
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作者 易龙 彭云 《机械设计与制造》 北大核心 2007年第2期4-6,共3页
随着计算机科学和有限元技术的发展,屈曲稳定性问题有限元数值求解技术已经比较成熟但是在大型复杂结构工程应用中还是由于计算量大、收敛困难而受到限制,特别是在需要反复迭代计算的优化过程中,更是受到该问题的困扰。针对某大型复合... 随着计算机科学和有限元技术的发展,屈曲稳定性问题有限元数值求解技术已经比较成熟但是在大型复杂结构工程应用中还是由于计算量大、收敛困难而受到限制,特别是在需要反复迭代计算的优化过程中,更是受到该问题的困扰。针对某大型复合材料机翼结构的考虑稳定性约束条件的优化问题,提取其典型盒段进行分析技术验证,研究计算效率和精度对于单元尺寸的要求。取误差限为1%,位移计算模型单元尺寸要求为150mm,而屈曲临界载荷系数计算模型单元尺寸要求为10mm。采用150mm的单元尺寸建立全结构模型进行位移求解,将位移计算结果应用于采用单元尺寸10mm建立的危险部位子模型进行稳定性求解,完成某复合材料机翼结构打样阶段优化设计,结构总质量较初始设计减轻24%,在满足精度要求的同时,计算效率显著提高。 展开更多
关键词 有限元法同曲稳定 子模型 优化设计
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Stokes方程的局部绝对稳定化有限元方法 被引量:3
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作者 祁瑞生 冯民富 刘丹 《四川大学学报(自然科学版)》 CAS CSCD 北大核心 2010年第3期436-440,共5页
对于Stokes方程求解问题,作者提出了局部绝对稳定有限元方法.该方法可以看成是Kechkar和Silvester方法从线性/常数元到任意混合元的推广,也可以看成是Douglas和Wang整体绝对稳定化有限元方法的局部稳定化改进.
关键词 局部绝对稳定有限元法 宏元 跳跃项
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拱桥非线性稳定分析 被引量:8
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作者 聂明皓 瞿国钊 张劲涛 《交通科技》 2007年第4期4-6,共3页
综合考虑了几何非线性和材料非线性对混凝土拱桥的影响,应用ANSYS对一座主跨为178 m的钢管混凝土拱桥的施工中最不利阶段以及成桥状态进行了稳定性分析,为此类桥梁的设计施工提供参考。
关键词 钢管混凝土拱桥稳定性分析有限元法
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非稳定渗流场对黏土心墙坝坝坡及心墙稳定的影响分析 被引量:1
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作者 袁浩瀚 焦延涛 《价值工程》 2019年第34期248-250,共3页
应用三维非稳定饱和-非饱和渗流有限元法建立xx水库枢纽区的三维有限元模型,对极端工况条件下(v=4.42m/d)坝体的非稳定渗流场进行了计算分析,结果表明1d内库水位由校核洪水位骤降至汛限水位,不会对坝坡及心墙的稳定造成不利影响。
关键词 三维非稳定饱和-非饱和渗流有限元法 稳定渗流场 坝坡
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含檐口双坡屋面风压风载的数值模拟 被引量:2
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作者 涂佳黄 周岱 李俊龙 《上海交通大学学报》 EI CAS CSCD 北大核心 2012年第1期119-125,共7页
基于雷诺时均N-S方程和Spalart-Allmaras湍流模型,运用稳定化流体有限元法数值模拟含檐口双坡低矮屋面的风压分布和风载体型系数,分析了檐口的竖向高度和外伸长度及屋面坡度等关键参数对屋面风载体型系数和周围流场的影响.结果表明:檐... 基于雷诺时均N-S方程和Spalart-Allmaras湍流模型,运用稳定化流体有限元法数值模拟含檐口双坡低矮屋面的风压分布和风载体型系数,分析了檐口的竖向高度和外伸长度及屋面坡度等关键参数对屋面风载体型系数和周围流场的影响.结果表明:檐口竖向高度对屋面风压分布和风载体型系数的影响较大;水平外伸檐口自身承受的吸力较大,而其长度对屋面风载体型系数影响较小;同时设置竖向和水平檐口时,对屋面风载体型系数的影响明显. 展开更多
关键词 稳定化流体有限元法 Spalart-Allmaras湍流模型 双坡屋面 风载体型系数
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某面板堆石坝渗流控制措施有效性评估 被引量:1
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作者 万小强 唐少龙 熊威 《江西水利科技》 2017年第3期188-192,共5页
本文基于ANSYS运用三维稳定渗流有限元法对某面板堆石坝进行渗流稳定性分析,研究了渗控措施设计方案下工程的渗流场分布及渗透稳定性,评价渗控措施的有效性,并对混凝土面板和防渗帷幕的渗透系数的变化对大坝渗流场的影响进行模拟.研究... 本文基于ANSYS运用三维稳定渗流有限元法对某面板堆石坝进行渗流稳定性分析,研究了渗控措施设计方案下工程的渗流场分布及渗透稳定性,评价渗控措施的有效性,并对混凝土面板和防渗帷幕的渗透系数的变化对大坝渗流场的影响进行模拟.研究结果表明:大坝防渗系统防渗效果较好,有效的控制了坝内渗流场的分布;混凝土面板及防渗帷幕渗透系数的改变对渗流场影响较大,在渗控系统的施工过程中须严格控制施工质量. 展开更多
关键词 面板堆石坝 三维稳定渗流有限元法 渗流分析 渗流场
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漕河水库大坝渗流分析及加固设计方案探讨 被引量:4
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作者 龚雪 方朝阳 《水电能源科学》 北大核心 2009年第4期58-60,53,共4页
分析了大坝坝体、坝基的渗漏原因,采用二维稳定渗流有限元法计算了坝体的渗流安全性,结果表明坝体、坝基存在渗流安全隐患。针对具体隐患部位,提出对坝体心墙部分采用冲抓套井加高心墙、开挖回填接高心墙、劈裂灌浆及对坝基部分采用帷... 分析了大坝坝体、坝基的渗漏原因,采用二维稳定渗流有限元法计算了坝体的渗流安全性,结果表明坝体、坝基存在渗流安全隐患。针对具体隐患部位,提出对坝体心墙部分采用冲抓套井加高心墙、开挖回填接高心墙、劈裂灌浆及对坝基部分采用帷幕灌浆、对输水涵管采用原涵管内套钢管等加固方案。通过加固后的渗流安全性分析,该措施可有效解决漕河水库的渗流及渗透稳定问题。 展开更多
关键词 大坝 坝基 渗流 渗流安全 二维稳定渗流有限元法 加固
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Study on the FEM design of reinforced earth retaining wall with geogrid 被引量:4
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作者 Song Yakun Zheng Yingren +1 位作者 Tang Xiaosong Zhang Yufang 《Engineering Sciences》 EI 2010年第3期71-80,共10页
At present,limit equilibrium method is often adopted in the design of reinforced earth retaining wall. Geotechnical engineers home and abroad have done a lot of work to improve the traditional calculation methods in r... At present,limit equilibrium method is often adopted in the design of reinforced earth retaining wall. Geotechnical engineers home and abroad have done a lot of work to improve the traditional calculation methods in recent years,while there are lots of defects. This paper first identifies the location of failure surface and safety factor through the finite element program of PLAXIS and then analyses the influencing factors of the stability of reinforced earth retaining wall with geogrid. The authors adopt strength reduction FEM (finite element method)in the design and stability analysis of reinforced earth retaining wall and have achieved some satisfying results. Without any assumptions,the new design method can automatically judge the failure mode of reinforced earth retaining wall,consider the influence of axial tensile stiffness of the reinforcement stripe on the stability of retaining wall,identify reasonable distance and length of the reinforcement stripe,and choose suitable parameters of reinforcement stripe,including strength,stiffness and pseudo-friction coefficient which makes the design optimal. It is proved through the calculation examples that this method is more reasonable,reliable and economical in the design of reinforced earth retaining wall. 展开更多
关键词 FEM strength reduction methods earth retaining walls optimization design
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New methods of safety evaluation for rock/soil mass surrounding tunnel under earthquake 被引量:1
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作者 程选生 DOWDING Charles H 田瑞瑞 《Journal of Central South University》 SCIE EI CAS 2014年第7期2935-2943,共9页
The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of eval... The objective of this work is to obtain the seismic safety coefficient and fracture surface and proceed with the seismic safety evaluation for the rock mass or soil mass surrounding a tunnel,and the limitation of evaluating seismic stability is considered using the pseudo-static strength reduction.By using the finite element software ANSYS and the strength reduction method,new methods of seismic safety evaluation for the rock mass or soil mass surrounding a tunnel are put forward,such as the dynamic finite element static shear strength reduction method and dynamic finite element shear strength reduction method.In order to prove the feasibility of the proposed methods,the results of numerical examples are compared with that of the pseudo-static strength reduction method.The results show that 1) the two methods are both feasible,and the plastic zone first appears near the bottom corners; 2) the safety factor of new method Ⅱ is smaller than that of new method I but generally,and the difference is very small.Therefore,in order to ensure the safety of the structure,two new methods are proposed to evaluate the seismic stability of the rock mass or soil mass surrounding a tunnel.A theoretical basis is provided for the seismic stability of the rock mass or soil mass and the lining surrounding a tunnel and also provided for the engineering application. 展开更多
关键词 TUNNEL rock or soil mass surrounding tunnel earthquake stability safety evaluation
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Research on the stability analysis and design of soil tunnel surrounding rock 被引量:2
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作者 Zheng Yingren Qiu Chenyu Xiao Qiang 《Engineering Sciences》 EI 2010年第3期57-70,共14页
The paper first analyzes the failure mechanism and mode of tunnel according to model experiments and mechanical calculation and then discusses the deficiency of taking the limit value of displacement around the tunnel... The paper first analyzes the failure mechanism and mode of tunnel according to model experiments and mechanical calculation and then discusses the deficiency of taking the limit value of displacement around the tunnel and the size of the plastic zone of surrounding rock as the criterion of stability. So the writers put forward the idea that the safety factor of surrounding rock calculated through strength reduction FEM(finit element method) should be regarded as the criterion of stability,which has strict mechanical basis and unified standard and would not be influenced by other factors. The paper also studies the safety factors of tunnel surrounding rock (safety factors of shear and tension failure) and lining and some methods of designing and calculating tunnels. At last,the writers take the loess tunnel for instance and show the design and calculation results of two-lane railway tunnel. 展开更多
关键词 stability of tunnel surrounding rock strength reduction FEM safety factor of shear safety factor of tension failure design method of tunnel
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Stability and reinforcement analysis of rock slope based on elasto-plastic finite element method 被引量:2
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作者 刘耀儒 武哲书 +2 位作者 常强 李波 杨强 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第7期2739-2751,共13页
The rigid body limit equilibrium method(RBLEM) and finite element method(FEM) are two widely used approaches for rock slope's stability analysis currently. RBLEM introduced plethoric assumptions; while traditional... The rigid body limit equilibrium method(RBLEM) and finite element method(FEM) are two widely used approaches for rock slope's stability analysis currently. RBLEM introduced plethoric assumptions; while traditional FEM relied on artificial factors when determining factor of safety(FOS) and sliding surfaces. Based on the definition of structure instability that an elasto-plastic structure is not stable if it is unable to satisfy simultaneously equilibrium condition, kinematical admissibility and constitutive equations under given external loads, deformation reinforcement theory(DRT) is developed. With this theory, plastic complementary energy(PCE) can be used to evaluate the overall stability of rock slope, and the unbalanced force beyond the yield surface could be the identification of local failure. Compared with traditional slope stability analysis approaches, the PCE norm curve to strength reduced factor is introduced and the unbalanced force is applied to the determination of key sliding surfaces and required reinforcement. Typical and important issues in rock slope stability are tested in TFINE(a three-dimensional nonlinear finite element program), which is further applied to several representatives of high rock slope's stability evaluation and reinforcement engineering practice in southwest of China. 展开更多
关键词 stability analysis rock slope plastic complementary energy(PCE) unbalanced forces elasto-plasticity FEM
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Reinforcement strength reduction in FEM for mechanically stabilized earth structures
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作者 薛剑峰 陈建峰 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第7期2691-2698,共8页
The factor of safety of mechanically stabilized earth(MSE) structures can be analyzed either using limit equilibrium method(LEM) or strength reduction method(SRM) in finite element/difference method. In LEM, the stren... The factor of safety of mechanically stabilized earth(MSE) structures can be analyzed either using limit equilibrium method(LEM) or strength reduction method(SRM) in finite element/difference method. In LEM, the strengths of the reinforcement members and soils are reduced with the same factor. While using the SRM, only soil strength is reduced during the calculation of the factor of safety. This causes inconsistence in calculating the factor of safety of the MSE structures. To overcome this, an iteration method is proposed to consider the strength reduction of the reinforcements in SRM. The method is demonstrated by using PLAXIS, a finite element software. The results show that the factor of safety converges after a few iterations. The reduction of strength has different effects on the factor of safety depending on the properties of the reinforcements and the soil, and failure modes. 展开更多
关键词 mechanically stabilized earth structures factor of safety strength reduction method iterative method
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Application of Program Generation Technology in Solving Heat and Flow Problems
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作者 Shui Wan Bangxian Wu Ningning Chen 《Journal of Thermal Science》 SCIE EI CAS CSCD 2007年第2期170-175,共6页
Based on a new DIY concept for software development, an automatic program-generating technology attached on a software system called as Finite Element Program Generator (FEPG) provides a platform of developing progr... Based on a new DIY concept for software development, an automatic program-generating technology attached on a software system called as Finite Element Program Generator (FEPG) provides a platform of developing programs, through which a scientific researcher can submit his special physico-mathematical problem to the system in a more direct and convenient way for solution. For solving flow and heat problems by using finite element method, the stabilization technologies and fraction-step methods are adopted to overcome the numerical difficul- ties caused mainly due to the dominated convection. A couple of benchmark problems are given in this paper as examples to illustrate the usage and the superiority of the automatic program generation technique, including the flow in a lid-driven cavity, the starting flow in a circular pipe, the natural convection in a square cavity, and the flow past a circular cylinder, etc. They are also shown as the verification of the algorithms. 展开更多
关键词 program generation technology heat and fluid flow stabilized finite element method operatorsplitting method
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Uniform analysis of a stabilized hybrid finite element method for Reissner-Mindlin plates 被引量:1
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作者 GUO YuanHui YU GuoZhu XIE XiaoPing 《Science China Mathematics》 SCIE 2013年第8期1727-1742,共16页
This paper presents a low order stabilized hybrid quadrilateral finite element method for ReissnerMindlin plates based on Hellinger-Reissner variational principle,which includes variables of displacements,shear stress... This paper presents a low order stabilized hybrid quadrilateral finite element method for ReissnerMindlin plates based on Hellinger-Reissner variational principle,which includes variables of displacements,shear stresses and bending moments.The approach uses continuous piecewise isoparametric bilinear interpolations for the approximations of the transverse displacement and rotation.The stabilization achieved by adding a stabilization term of least-squares to the original hybrid scheme,allows independent approximations of the stresses and moments.The stress approximation adopts a piecewise independent 4-parameter mode satisfying an accuracy-enhanced condition.The approximation of moments employs a piecewise-independent 5-parameter mode.This method can be viewed as a stabilized version of the hybrid finite element scheme proposed in [Carstensen C,Xie X,Yu G,et al.A priori and a posteriori analysis for a locking-free low order quadrilateral hybrid finite element for Reissner-Mindlin plates.Comput Methods Appl Mech Engrg,2011,200:1161-1175],where the approximations of stresses and moments are required to satisfy an equilibrium criterion.A priori error analysis shows that the method is uniform with respect to the plate thickness t.Numerical experiments confirm the theoretical results. 展开更多
关键词 Reissner-Mindlin plate stabilized method hybrid finite element quadrilateral element
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Stability analysis and a priori error estimate of explicit Runge-Kutta discontinuous Galerkin methods for correlated random walk with density-dependent turning rates
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作者 LU JianFang SHU Chi-Wang ZHANG MengPing 《Science China Mathematics》 SCIE 2013年第12期2645-2676,共32页
In this paper,we analyze the explicit Runge-Kutta discontinuous Galerkin(RKDG)methods for the semilinear hyperbolic system of a correlated random walk model describing movement of animals and cells in biology.The RKDG... In this paper,we analyze the explicit Runge-Kutta discontinuous Galerkin(RKDG)methods for the semilinear hyperbolic system of a correlated random walk model describing movement of animals and cells in biology.The RKDG methods use a third order explicit total-variation-diminishing Runge-Kutta(TVDRK3)time discretization and upwinding numerical fluxes.By using the energy method,under a standard CourantFriedrichs-Lewy(CFL)condition,we obtain L2stability for general solutions and a priori error estimates when the solutions are smooth enough.The theoretical results are proved for piecewise polynomials with any degree k 1.Finally,since the solutions to this system are non-negative,we discuss a positivity-preserving limiter to preserve positivity without compromising accuracy.Numerical results are provided to demonstrate these RKDG methods. 展开更多
关键词 discontinuous Galerkin method explicit Runge-Kutta method stability error estimates corre-lated random walk positivity-preserving
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