用加劲肋加强的四边简支矩形板屈曲

研究了用加劲肋加强的板的局部屈曲.用能量法求解双向均匀受压和受剪的,加劲肋加强的四边简支矩形板的稳定性问题,讨论了加劲肋对屈曲荷载的影响.     

扁平钢箱梁U肋加劲板的加载偏心

以一座主跨1 088 m扁平钢箱梁斜拉桥为例,分析了扁平钢箱梁U肋加劲板加载偏心的大小及对U肋加劲板稳定承载力的影响.首先采用包括梁单元和板壳单元的混合建模方法建立全桥有限元模型,在计算加载偏心的梁段采用壳单元,其他部位采用梁单元.根据有限元方法求得U肋加劲板截面的应力分布,利用积分方法计算U肋加劲板的内力和加载偏心,并将加载偏心对承载力的影响等效为初始几何弯曲.研究结果表明,U肋加劲板的加载偏心率约为0.17,最大为0.35,相当于L/250的初始弯曲,该值远大于规范规定的最大几何偏心,因此计算扁平钢箱梁U肋加劲板稳定承载力时需考虑加载偏心的影响.     

抗弯刚度比对加劲板屈曲性能的影响

以一大型薄壁钢结构的加劲板为研究对象,采用有限元方法,考虑了13种不同的刚度比、多种不同的加劲肋布置方式以及边界条件等因素,分析了加劲板线性屈曲和非线性屈曲性能.抗弯刚度比对加劲板的屈曲性能影响显著,加劲板最佳抗弯刚度比将其线性屈曲模态划分为整体屈曲和局部屈曲,其值为10～20.加劲板非线性屈曲荷载随抗弯刚度比增大而提高.另外,在加载方向增加加劲肋布置可以提高加劲板局部屈曲荷载,在非加载方向增加加劲肋布置对加劲板的局部屈曲性能影响较小.     

初始缺陷对除尘器壳体立柱轴压稳定性的影响

为考虑除尘装备壳体加劲钢板墙板-H型钢立柱结构体系中初始缺陷的影响,采用非线性有限元方法,研究初始几何缺陷和焊接缺陷对立柱承受轴向压力时失稳模态和稳定承载力的影响。研究结果表明:较为不利的初始几何缺陷形态是立柱截面的初始弯扭变形,较为不利的发生最大初始几何变形的位置在靠近柱顶的高轴力区。焊接残余变形对壳体立柱轴压稳定性影响很小,焊接残余应力对壳体立柱稳定性有微小的有利影响。构建壳体立柱轴压稳定性数值计算模型时,可以引入施加定向干扰的完善结构极值点模态缺陷,以充分考虑初始几何缺陷影响;无需考虑焊接残余应力影响。     

大型反应器加劲薄钢板结构屈曲性能

通过有限元方法分析了大型反应器钢结构体系的受力与变形的薄弱位置,并对反应器中大量使用的加劲薄钢板的屈曲性能进行了研究. 在此基础上,实验分析了加劲板的稳定性. 结果表明:矩形薄钢板开孔周围加加劲肋时,加劲肋对板起到嵌固作用;对于此反应器整体结构来说,薄板选择L形加劲肋最优;对于带有加劲肋的薄板,边界约束条件越强,临界屈曲荷载越大,板越不易发生屈曲. 实验和数值结果有较好的一致性.     

夹层矩形板的非线性动力屈曲

研究了夹层矩形板的非线性动力屈曲问题,基于Reissner假设和Hamilton原理下的夹层矩形板的非线性运动控制方程,应用伽辽金方法和双参数摄动法确定四边简支夹层矩形板在纵向简谐载荷作用下的非线性动力不稳定区的边界,并对影响动力稳定性的若干因素进行探讨.     

平齐端板连接火灾下性能的有限元分析

利用有限元分析软件ANSYS对高温下平齐式端板连接性能,节点的构造及节点参数的选取对结构的整体稳定性及节点破坏模式的影响进行了分析.发现:端板厚度对节点的初始转动刚度影响较大,载荷比对转角的影响较大;设置承压加劲肋可明显减小节点域内的塑性应变,改善柱腹板的受力状态,提高柱稳定性,从而保证钢框架整体的稳定性.     

悬索桥桥塔横梁施工支架的非线性稳定性分析

从结构稳定性的基本概念出发,分析了理想结构和实际结构分别可能出现的失稳类型,介绍了目前在ANSYS中对各种稳定性分析所采用的方法.针对一实际悬索桥桥塔横梁的施工支架,考虑施工中可能产生的初始缺陷及横向偏压等,利用ANSYS并考虑几何非线性和材料非线性,对其进行了分析.通过对各种初始缺陷和偏压状况下计算结果的比较,得出钢管支架失稳的规律.     

初始缺陷对正交叠层圆柱曲板临界载荷的影响

本文应用动态松弛法(DRM)研究了承受均匀轴向压力的硼/环氧复合材料正交叠层(90°/0°)圆柱曲板在加载过程中的大挠度挠曲特性和初始几何缺陷对临界载荷的影响。文中考虑了两种弯曲边界条件;一种是四边简支;另一种是承载边为夹支而非承载边为简支。面內边界条件则假定板的周边在几何上不受约束。数值结果表明,初始几何缺陷使临界载荷显著下降,且下降的幅度与缺陷的严重程度及边界条件有关。     

带端板加劲肋的外伸端板连接的梁柱节点试验

为了讨论加劲肋对连接性能的影响,对带端板加劲肋的外伸端板连接的梁柱节点进行了循环荷载作用下试验研究.分析了端板、端板加劲肋、梁柱翼缘和腹板在荷载作用下的应力情况,确定了这种连接的受力性能及破坏模式,分析此类连接的滞回曲线、连接初始刚度、承载能力和延性特征.试验结果表明,加劲肋是提高节点性能的一项有效措施.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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     

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

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