轴对称几何非线性问题中的无网格算法

应用无网格伽辽金法对轴对称几何非线性问题进行了分析。在小变形假设的条件下，利用几何非线性的应变-位移关系，基于线性弹性本构关系，推导了无网格法的计算控制方程，并采用Newton—Raphson迭代法来求解非线性方程，初步计算了压力管道的几何非线性问题。由于无网格方法中的形函数不具备Kroneckerdelta性质，采用罚方法来实现本质边界条件。数值实例表明．无网格伽辽金法在处理轴对称几何非线性问题时，具有较高的计算精度，是一种有效的数值计算方法。     

路堤软土地基沉降有限元非线性分析

用Biot固结有限元法对路堤软基沉降作非线性有限元分析 ,计算中考虑了土体侧向变形、水平向渗流对沉降的影响 ;采用非线性本构模型 ,考虑了土体应力、应变关系的非线性特性 ;考虑了施工的逐级加载 .计算结果与实测吻合较好 .     

软土路基变形规律现场监测及FLAC模拟研究

以杭州绕城高速公路K28+830粉喷水泥搅拌桩处理试验段为工程背景,采用现场监测及FLAC2D数值模拟相结合的方法,对软土的蠕变-固结变形规律进行了研究.给出了路基变形现场监测方案,进行了软土路基变形平面FLAC2D模拟计算.结果表明,粉喷水泥搅拌桩使软土路基沉降和水平位移明显减小,地基稳定性增强,适宜加固饱和软粘土地基,尤其适合于桥头有相对硬层作为持力层的地段.FLAC2D计算结果总体上能反映实测的路基变形发展趋势,计算结果与现场监测结果基本一致.粘塑性蠕变本构模型可用于软土路基沉降预测预报,对软土路基沉降控制有一定参考价值.     

高速公路软基土体固结变形的数值计算方法

该文在给出反映土体固结流变性的本构方程基础上，提出一种高速公路软基土体固结变形的数值计算方法。该方法依据有效应力增量方程式，利用西瓦伦公式计算有效应力值，采用逐步递推迭代方法，实现土体固结变形的计算。     

软土路基粘弹塑性大应变分析的工程应用

采用粘弹塑(西原)本构关系模拟土骨架的材料非线性、更新的拉格朗日法描述软土的几何非线性,推导用于增量分析的饱和土体双重非线性U.L.J.格式平衡方程和连续性方程,编制软土路基大型实用化有限元分析程序,利用该程序对某高速公路的实测断面分别进行大应变、小应变分析.数值模拟结果和现场实测结果的对比分析表明:大、小应变分析结果的差异随应力水平的提高和时间的延长而上升,其地表沉降、地基沉降、水平位移、孔隙水压力的最大相对误差分别为16.39%,20.23%,27.8%和22.75%,说明对软土路基进行大应变分析很有必要;采用室内试验确定的计算参数进行分析时,计算结果虽能较好地模拟地基应力和位移的发展趋势,但其值有较大差别,说明必须寻求更加合理的计算参数确定方法以提高数值模拟精度.     

变荷载下任意层地基一维非线性固结的数值分析

采用双曲线型的土体应力应变关系和渗透系数k随孔隙比变化的关系式,不对固结系数作任何假设,建立了考虑荷载变化的任意层地基的一维非线性固结控制方程,并用简化加权隐式差分格式对上述非线性固结控制方程进行数值计算。以某四层地基为例,通过与太沙基线性固结理论的比较,揭示了非线性因素对饱和成层软土地基一维固结的影响及通常情况下考虑非线性因素影响的必要性。     

考虑非Darcy渗流和自重应力的一维固结分析

基于饱和黏土中渗流的非Darcy特性和变形的非线性,考虑土体埋深和自重应力的影响,修正了Terzaghi 1维固结方程.为简化计算,建立了以有效应力为求解对象的非线性控制方程,并采用有限差分法建立隐式差分格式对方程进行求解.探讨了综合考虑土体渗流非Darcy特性、埋深、自重应力和变形非线性时的固结特性.计算结果表明:考虑土体自重应力时的孔压消散速率和地基沉降速率都要大于不考虑土体自重时的情况;综合考虑土体自重、非Darcy渗流特性和变形非线性的孔压消散速率和地基沉降速率都可能出现前期快于Terzaghi固结理论解而后期相反的情况.     

饱和软土的弹塑性大变形有限元平面固结分析

基于非线性连续介质力学的基本理论,采用Ｔｏｔａｌ Ｌａｇｒａｎｇｉａｎ法（即ＴＬ法）。在原有的小变形弹塑性软土固结程序Ｃｏｎｄｅｐ基础上,编制了二维大变形平面固结问题有限元计算程序,其中采用软土修正Ｃａｍ－ｃｌａｙ本构模型时,考虑了刚性旋转不变性的影响。验证了程序的正确性,并就一典型的软土地基进行计算,所得结果与小变形理论结果作了对比。     

真空动力固结饱和软土地基非线性固结解析解

为了更深入研究饱和软土地基真空动力固结机理,基于有限应变理论建立了考虑多种因素影响的真空动力固结饱和软土地基非线性固结方程,并通过变量代换和分离变量求出方程解析解,研究结果表明:按照沉降和孔压定义的软土地基平均固结度结果差值受大变形时间因数影响明显,呈现出先增大后缩小特征,且在任意时刻饱和软土地基沉降发展速率明显快于超静孔压消散速率;计算解同室内试验结果变化趋势基本一致,表明了非线性固结方程的合理性,且动力固结和真空降水时间间隔不宜超过1 d。     

海滨大道水泥双向搅拌桩施工技术

0引言 随着我国公路建设和改造的迅猛发展，软基加固技术也不断的进步。软基承载力低，地基沉降变形大，而且沉降稳定历时比较长。在比较深厚的软粘土（淤泥土）层上，结构物基础的沉降往往需要几年。甚至几十年。淤泥土地基是在工程建设中经常遇到需要处理的软弱地基，它们广泛地分布在我国沿海以及内地河流两岸和湖泊地区。特别是填海的一些地区。路基填筑之前如果地基不够坚固，建成后路面严重沉降，为防止填筑后地基下沉拉裂造成基床不稳定等事故，需要对软地基进行处理，使其沉降变得更小，提高软地基的固结度和稳定性至设计要求。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

正~~